Help! GMC Jimmy hesitation / miss

04SlvrJetta

Veteran Member
Joined
Aug 1, 2007
Location
Wheeling, WV
TDI
15 Passat SE DSG
I hope I'm in the right spot for this question. My wife's car is a 98 Jimmy (big mistake) with about 105k miles. Anyway, it has started this hesitation and rough idle. It is an intermittent problem..sometimes there and sometimes non-existent. Engine speed or temp don't seem to matter. This problem comes and goes cold or hot, idle or driving, city or highway, 20 or 80 mph. Yes 80, but my Jetta TDI feels better at 115 than this vehicle feels at 70! When the problem doesn't show it's ugly head, the vehicle runs fantastic. This is probably due to the rebuild at 89k! It has thrown a misfire code in the past, but I have since checked several times and get no codes with my scanner. I suspected a vacuum leak, but can not find one and ruled it out since it is not there all the time. I also have rapped on the ECM (Haynes recommendation) to try to determine if there may be an electrical short/long. One day I was looking/listening for loose hoses, etc and heard a snapping noise. I was certain that I had a bad plug wire since the hesitation seemed to match up with this snapping noise. Well, I changed the wires and the problem disappeared for a couple of days and came right back. Can anyone give me some advice? I suspect it is fuel or ignition related. The rotor and cap are good. I have replaced the air filter, cleaned the MAF sensor, run a few cans of injector cleaner and replaced the pcv valve. Timing is not adjustable. The (in-tank) fuel pump/sending unit was replaced a little over a year ago. I have a Haynes book, but it doesn't offer up much. I have thought about the fuel cap and ign coil. They're cheap and replacing would rule them out. Any suggestions are appreciated! :confused:
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
This is a VERY common issue and I see them all the time.... The Blazers are really not as big of a P.O.S. as people make them out to be. The 4.3 (W or X code) is an awesome engine. They are almost always a victim of a bad technician that doesn't know how to diagnose anything without just replacing parts until it's fixed.. My dad's 2000 has 240k and runs like a brand new one.. Gets 22mpg average as well..

Take the EGR valve off and clean it with some carb cleaner or brake cleaner... What happens with the 4.3's is they get a bunch of carbon built up in the EGR passages(sound familiar?) and when a piece breaks off somewhere it usually gets stuck in the EGR valve and hangs it open slightly, causing a rough idle.. Usually a few moderately hard accelerations will clear it out.. Full throttle the ECM will keep the EGR off so WOT won't clear it out.. You want to have heavy enough throttle for the computer to command the EGR valve all the way open so the chunk will come out.. If that doesn't work the only way to get the chunk out is to take the valve off and take the piece out..

The snapping noise is Definitely spark jumping somewhere.. You replaced the cap and rotor right? I hope so.. I know they are pretty expensive for the newer 4.3, but they need to be done if they are 10 years old... Don't get the cheap ones from Autozone either.. Double and triple check that all 7 wires are fully seated and not rubbing on anything hot or sharp.. It's common for the new wires not to click on the cap because they aren't far enough through the boots..


You might also have more than one issue happening here as well..

These engines have one small thing in common with the TDI... If you really drive them easy, they get all crapped up and start causing a lot of headache.. Drive the truck a little aggressive sometimes, but not hard enough to trash the weak transmission that GM decided to put in there.. It's the same overdrive trans used in a lot of 3/4 ton trucks and suburbans, but they somehow decided to not put enough friction plates in them for the 6 cylinder applications and they burn up, usually 3/4 goes out first, followed by 2nd.. There's a real simple mod you can do with the pan off to make them shift firmer and last longer by turning up the line pressure a little (sound familiar too?)..
 
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04SlvrJetta

Veteran Member
Joined
Aug 1, 2007
Location
Wheeling, WV
TDI
15 Passat SE DSG
Thank you for your thorough response! The vehicle does run well (other than this hesitation) but we have replaced many, many things. Most of them under warranty and some for the 2nd or 3rd time. I guess my perception of GM is that they do keep the costs down on some models, but they are under-engineered and wait far too long to make changes to 'weak points' such as our front suspension which even after regular lubrication seems to be shot after about 2 sets of tires. Or my engine that failed 11,000 miles before the plugs were due to be changed! This is partly my fault, though for not being more persistent with the dealer when we had an internal coolant leak since day one! I also griped about fuel consumption since day one, but was assured that 15 was 'bout what everyone gets. We get 15 mpg up or down hill, into or with the wind, hard or easy driving, city or highway. When we went on our honeymoon we did a lot of driving and I think a couple of pure highway tanks averaged 16! I got 17 in town once, but I am sure that I had just not completely filled the tank! I am amazed at 22MPG! Is it city or highway? What can I do to get that? Dealer was were kind enough to clean the intake for me at about 28K miles for $150! Now, there's money well spent. :mad: With a car dealer like that, who needs enemies! We've been lucky with the trans so far. I probably should not have said that. My luck...it'll break tomorrow. I have had it serviced with the 'flush' type that uses 16 qts of fluid. It seemed to help with the shifting. About this mod you mentioned...is this something I can do? That is, without messing something up! You say 'does this sound familiar, too' but it doesn't. What is the comparison on a TDI? Something I don't know about yet, maybe?

I notice that you make reference to a couple of items here sounding familiar or being a little like a TDI. I have to agree and disagree. I disagree because I have not experienced any problems with my TDI which is now approaching 100k miles (time for the timing belt service $). The only problem that I had was traced to an EGR cooler recall and an owner that had to 'fix it right' after the dlr had done the recall! Now if there's a way to impress your wife or girlfriend...This IS NOT it! :rolleyes: I say go with the flowers or something! After some prodding my dlr used a helicoil or something to repair the damaged threads and replaced some bolts. Of course they still had diagnosis and time in it but $240 was much better than the $960 est they gave me initially when they told me that my EGR cooler needed replaced. The tune changed a little when I said I would pay for the diagnosis and take it home and repair it the way a mechanic (not parts changer) would. ;) I don't drive the TDI like a race car (ok, not all the time), but it doesn't get babied like the Jimmy. This is where I have to agree about driving too easy. If the TDI got the drive that the Jimmy does it would be clogged up bad. The Jimmy just doesn't get the dog crap run out of it often enough! I drive the TDI all week and Deb (my wife) drives the Jimmy. On the weekend (yes, it's painful) the TDI sits since I clock 800 miles/week commuting so I drive the Jimmy and when given the opportunity I blow the cobwebs out of it!

I don't know if I'll get to this EGR before this weekend, but I will try it and let you know what happens. Thanks again for the reply!
 

fursty

Active member
Joined
Dec 24, 2006
Location
Webster New York
TDI
Black 2002 Jetta
When you replace the distributor cap and rotor, take some compressed air and blow out the two vents on the base under the rotor. They do have a screen that will plug up and the distributor is unable to dry out. Corrosion on the cap terminals will occur thus the misfires that you might be having. It is common with this engine as said above. My S-10 will do the same thing after awhile. This procedure cleared it up the last time it occured.
 

tttthumper

Veteran Member
Joined
Jan 9, 2008
Location
Pickering, Ontario
TDI
2006 Jetta TDI
I had a 1996 GMC Jimmy, that I drove for 10 years.
Reached 400,000 kms (~250,000 miles) and at the end I was still getting 25mpg on highway.

It ran great, the 4.3 was awesome and never gave me any real problems.

I do remember having a hesitation problem. I changed the rotor and cap, and it still didn't go away.
Going from memory here, I recall that either my sparkplug cracked, and/or the boot wasn't seated on the plug properly, and I was arcing. (or maybe both occurences happened)

Plus doublecheck the one sparkplug that's right beside the steering column, I had one mechanic (I'm 95% sure) he did not change that spark plug and upon changing spark plugs next time, I saw all the junk on it.

It's a PITA to undo steering column just to change a spark plug, or need a special rachet tool.

Peter
 

04SlvrJetta

Veteran Member
Joined
Aug 1, 2007
Location
Wheeling, WV
TDI
15 Passat SE DSG
A quarter of a million miles? If you didn't say GMC Jimmy I would be asking if you were talking about some other car that you nicknamed 'Jimmy'! ;)

As I said in earlier posts I am partly to blame for the engine demise. If I have a stealer giving me the run around and excuses like this again I will not back down!

Other than the hesitation, we have not had any problems since the rebuild at 89,000 mi. We have about 105k on it now. The plugs were placed with platinum tipped ones when the rebuild was done. I would guess they were put in before the engine went back in, but It's interesting to me that you mention the plug behind the steering column. I think that is cyl#3 which is the cyl that gave a misfire code.

If you run into a clearance problem again, try a set of socket adaptors that have a head on them like a bolt. I got mine from Craftsman. There was 1/4", 3/8" and 1/2" drive you just turn them with a wrench like a bolt head. This worked for the Jimmy....and it was the only thing that I found that did work.

What really frustrates me is that I know GM is probably putting out some better products now than in '98. And let's face it...there's a lemon in every crowd. Although I can not really sell myself on this because I have known so many people that have had the same problems we have had with our Jimmy. Anyhow, back to what frustrates me...my wife won't even look at a GM car because of this ownership experience! She won't even comment on it's looks! To her, why look when you have already decided that you will not buy. Unreasonable as this may be, it is how she feels!
 

ceadmin

New member
Joined
Feb 19, 2008
Location
IA
TDI
None
'99 Blazer - same issues

I feel compelled to add that my experience with my wife's 99 Blazer is a POS as well from GM. We bought the truck at 35k and had a new engine and a rebuilt transmission by 38k. The coolant had leaked (we didn't know this) into the engine and ate away at it until I threw a rod pulling my boat. We lost only first gear on the transmission for some unexplained reason and we had a rebuilt, no problems since, but:

We have replaced all wheel bearings, front hubs, upper/lower ball joints, Heater Core, Rear Window Motor, 4x4 switch, rotors (like crazy), etc...etc.... The engine is still solid at 190k but I am tired of putting money into this thing and we have it up for sale. When its fixed, it runs great, its just that it doesn't take long before something else needs fixin.

Also because of this, my wife has definately (and I to an extent) have taken GM off our list of vehicles we will drive. Although I would like to take a look at the 2010 1500 diesels when they come out and do a comparison against the F150 diesel.

-----------------------------------------------
ETA: Change your spark plugs again and the plug wires and your problem should go away. And boy isn't number 3 a ***** to change!
 

El Dobro

Top Post Dawg
Joined
Feb 21, 2006
Location
NJ
TDI
2017 Bolt EV Premier, 2023 Bolt EUV Premier
If the engine was rebuilt, the distributor could be back in where the timing is off just enough for it to not throw a timing retard code but to give you the hesitation. Play it safe and check the timing.
 

04SlvrJetta

Veteran Member
Joined
Aug 1, 2007
Location
Wheeling, WV
TDI
15 Passat SE DSG
El Dobro: I can check this, but would you agree that this would cause a consistent problem and that this problem would have been there ever since we got it back? W have put 16k on it and this problem surfaced only the past 2-3k miles.

ceadmin: Your story sounds much more like most that I have heard. One night we left wal-mart and as I was loading groceries this guy starts asking me about our Jimmy. As I closed the tailgate we continued the conversation. He and I basically would name a part and then nod the affirmative that we had fixed it, too. After this went on for 2-3 min I get in the car and my wife says "that guy doesn't look familiar - where do you know him from" My reply "I don't know him but we have much in common. We have replaced all of the same parts on our Jimmy that he has replaced on his Blazer-well, except for the fuel pump!"

Nice, huh? I told that guy that I had something to look forward to and about a year later I, too replaced my fuel pump.

I think that it is fair to say that we have replaced some part on this car more frequently than we have changed the oil. I change it every 3,000 miles!

Hell, I thought it was bad that my spark plugs outlasted the engine.
I don't have the maintenance schedule memorized, but I'm thinking that for you the idea was why bother to change the air filter and trans fluid...just rebuild them instead.

What is strange, though is perception...even with the repair cost for the engine rebuild I think we have less money in repairs than my mother-in-law has on her comparable year/mileage Pathfinder. After the warranty I have done most of my repairs where she gets them done at the Nissan dealer so that's part of the $ difference. She doesn't want to part with her Pathfinder and says when she has to get a new car it will be another Pathfinder. I think the difference is that we just get to wait all the time for what comes next! Thanks for the reply!
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
El Dobro said:
If the engine was rebuilt, the distributor could be back in where the timing is off just enough for it to not throw a timing retard code but to give you the hesitation. Play it safe and check the timing.
The timing is NOT adjustable on the later 4.3's... The distributor doesn't turn in the intake more than 2 degrees either direction.. You check the cam synch with a scan tool.. It will throw a code if it's more than a few degrees off, but even that little rotation of the distributor does not affect the ignition timing at all. It pretty much either runs or it doesn't as far as distributor alignment. The computer uses the crankshaft position sensor for ignition timing..

The TBI engines are a different story..
 

El Dobro

Top Post Dawg
Joined
Feb 21, 2006
Location
NJ
TDI
2017 Bolt EV Premier, 2023 Bolt EUV Premier
I'm going by what one of the techs at work told me when I showed him the thread. I didn't ask any of the A techs because they already split for the weekend, but he's worked at private shops and has come up with some good answers. He also said that he didn't see any mention of the fuel filter being changed or a fuel pressure test being done.
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
Actually some of the 4.3's the distributor did rotate and even though it had no affect on the actual timing, the rotor can be mis-aligned and cause quite the annoying hiccup.. Usually codes are thrown if it's that far off..

Another thing that happens a LOT.... The MAF gets some dirt on the sensing element and sends a delayed signal to the ECM.. This will cause some hesitation without any codes.. Take the MAF out and spray it with some electrical parts cleaner (Napa has it) and take it for a spin again.. A dirty MAF element on a 4.3 will kill the fuel mileage in a heartbeat... You can unplug it and drive it as well, if the hesitation goes away, then the problem lies there..

Checking fuel pressure is a good idea but if it has enough pressure to fire up cold, it's good... The spec is 60-66psi and they won't even think about firing with any less than 55psi..

A clogged fuel filter will cause more of a problem under a heavy load than anything.. If the truck runs well full throttle, then the fuel filter ia not causing your hesitation...
 

bluesmoker

Veteran Member
Joined
Jun 7, 2006
Location
Maple Ridge, B.C.
TDI
2004 pd 5 speed tip
Listen fellas , I just sold my 97 gmc sonoma (mechanically identical to the blazer)

a MAJOR POS :mad:

here is the "short parts list" over 150, 000km

windshield wiper module, ball joints, center link, steering box, shocks twice, clutch, rear end (despite regular oil changes) rear bearings, door pins (doors sagged) back up light switch, rotors at every brake job (the brakes are undersized and warp the rotors) the interior plastic is falling off everywhere, the center console dry rotted and collapsed, the sunvisor fell off, it eats batteries (3 so far) oil cooler lines leak constantly (replaced twice) the truck is not factory undercoated and rusts virtually instantaneously , door seals for every door (how nice to open your vehicle to find it full of water), starter "control relay failed" and left me stranded....


etc..............etc.........

I just purchased a single owner 98 tdi with 114k, it cant possibly be anywhere near as bad as that GMC POS.

never again will I purchase any vehicle made in north america
 

04SlvrJetta

Veteran Member
Joined
Aug 1, 2007
Location
Wheeling, WV
TDI
15 Passat SE DSG
Thanks for all of the replies! Here are some responses to points that you all raised:

TDIJetta99 - I did the EGR cleaning. There was soot on it. It was built up more, but only about as coarse as what you would find inside a tailpipe (well, maybe on a diesel). I did not see anything holding it open, but I cleaned it and let it dry. It moves pretty easily :confused: , but I tried blowing through it and couldn't. The problem may have improved slightly at idle, but while I was under the hood I manually operated the throttle and if I open it really slowly I get no hesitation. If I snap it open the engine falters when the increased fuel hits.

TDIJetta99 and El Dobro - my thoughts on a couple of issues....

Timing - I am familiar with the distributor. It only goes in one way, but you have to be certain that the rotor is pointing where it should as it drops in. My basic scan tool (I think it is actron? brand) has not given any codes. Will a basic tool pick these up, or do I need a more advanced one? Also, this prob was not here for quite some time after the rebuild. The distributor has not been taken out since. Could the crank pos sensor be a prob? Would it throw a code?

MAF - I have cleaned it with MAF sensor cleaner - no change. I can try unplugging.

Fuel delivery - I may not have mentioned it, but the filter has been changed. The fuel pump was a suspicion of mine because it has been changed since the eng rebuild. Maybe I was not correct to do so, but I ruled it out as a suspect on the grounds that when I don't have hesitation, I have very strong power all through the operating range. Have you heard of a fuel pump/sending unit deliver inconsistend fuel pressure? Is this hard to test? Equipment expensive? When I was talking about this the other night my wife reminded me that she has had a couple of occurrences of hard starting. In one case the eng rolled over for 20+ seconds before firing.

Ignition - I have wondered if I could have an ignition coil breaking down electrically. Is there a test that can prove that it is good. Oh, also, I re-checked all of the wires and boots. I see no signs of rubbing (I was very careful to route them well and snap them in the looms when I put the new ones on). I do not hear any spark 'snapping' sound like i heard before.

bluesmoker - not that it's anything to feel good about, but your parts list has mine beat...hands down! :( A couple of these other guys have some good things to say. I have actually had good luck with the body. No rust at all. I just replaced the original shocks about a month ago. Other than the cat converter my exh is all original. the cat was replaced under warranty. I just don't understand how some are OK and most are sooooo bad. :confused: I wonder if these were made in more than one plant? Good luck with your TDI! I am confident that you're better off with it than the Sonoma!
 
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