Rough idle problem

My wife's '03 Golf TDI is experiencing a rough idle which is not evident when the car is underway. She took it to the local dealer (Oklahoma City) who suggested it might be in the fuel line. She ran it down to near empty and refilled. The rough idle is still present.

I also have the same year/model and have not had such a problem. When she filled the tank, she waited until I needed a refill as well so that we would be running on the same batch of fuel. She still has the problem but I do not.

Before we take it back to the dealer's service bay I want to ask other TDI owners to share any similar solution/fix.

Thanks

well your first problem was taking it to Cable, snicker. Hi guy, I live in Yukon, and may be biased since I have had nothing but slipshod work from them (if that is where you took it). I also had a rough idle on my 98 Jetta, and it would even do it while I was accelerating when cold, but when warm it would go away. I don't know if it is your MAF, being so new, but I took mine out and cleaned it with some electric part spray cleaner, and it seemed to help quite a bit...it could also have been the act of reseating the electric plug, dunno. FWIW, make sure you get them to write down on your estimate sheet exactly what they will do for you, otherwise you'll be frustrated. Good luck.

Hey I am getting my VAG-COM cable in Monday, and if you want to look at codes, let's get together...come to think of it, I hope the shareware version of it will look at a 2003...never thought of that...anyway, I'll be here, and there are also some more tdiers around here...lightwave is here in okc, and hover one is in lawton. Nice to know there are some more around here /images/graemlins/smile.gif.

Thanks for the quick response Rickster. I have the same reservation about Cable and being mechanical impaired puts me at a great dissadvantage.

The problem appeared shortly before the first scheduled service. It is not nearly as pronounced when cold as when the engine is warm. As soon as she starts to accelerate, and during driving at any speed, it goes away.

Have you found any good TDI mechanics in the OKC area?

Might have something to do with IQ.

No doubt that my IQ is pretty low regarding diesel mechanics but, since my IQ doesn't have anything to do with rough idle, I assume you are referring to the dealer.

And it could be the start of injection timing. When you get the VAG-COM access, I suggest using the TDI Timing Graph add-on software (from Ross-Tech) to verify the timing as the first step.

By IQ he's referring to "injection quantity" ... Have a look at what the TDIFAQ says about this; a minor adjustment with VAG-COM should fix it.

Okcjack, as soon as I get the cable and the software setup you are welcome to come by...I will say this about Cable...I waxed the cover to my diag port when I took it in once to check for the cold missing problem...they said they didn't find any problems, but the wax was never disturbed...i don't know if they can check problems using some other port, but that soured me on them. If you are willing to wait until you and I learn enough about this software then hopefully we can use the knowledge on this place to make a fix.

On that note, can someone answer a question? On Wingnuts's advice I bought the obd-II cable from Greg's site...I also saw that there may be two flavors of the VAG-COM software? Will the $99 registration do everything with this cable? No limitations on model year or function? I tried to figure this out but am unclear so far.

rough idle? check fuel filter drain and/or replace. check for fuel leaks anywhere and in return lines. egr clogged? n109 seated properly? any codes? rough idle huh? umm let see vacuum leak maybe, brakes work ok? do u have to press pedal hard?

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rough idle? check fuel filter drain and/or replace. check for fuel leaks anywhere and in return lines. egr clogged? n109 seated properly? any codes? rough idle huh? umm let see vacuum leak maybe, brakes work ok? do u have to press pedal hard?

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Holy moly! (laughing hard)...I don't know about Jack, but I nearly went out and put my Jetta out of its misery when I read all those possibilities /images/graemlins/smile.gif...i'm half expecting a truckload of error codes when I finally get VC up and running /images/graemlins/smile.gif. I wouldn't expect a 2003 to have more than one or two of those possible causes, but we will see. I hope to get the cable in today, Jack, unless the USPS takes off for Groundhog Day.

It will go to Cable VW today or tomorrow and will keep you posted.

just trying to cover most things, you would be amazed sometimes if u miss something so small or not even related to it but it fixes the problem

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just trying to cover most things, you would be amazed sometimes if u miss something so small or not even related to it but it fixes the problem

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I know what you mean, after reading on this forum for the past year or so...I wasn't laughing at the quality of your post, by the way, just how it reminded me suddenly of all the things that CAN cause an issue...I wrote it all down /images/graemlins/smile.gif.

Jack, I got my cable in today, only it isn't a cable, it's a plug that goes into the diag port and then you need a serial cable to go on it...been so long without a serial device I had to go get one /images/graemlins/smile.gif. It works on my A3...I did have the "01050 glow plug monitoring/35-10-intermittent" message on there. Was kind of neat to see the whole thing working. I only have one concern at the moment...if I register the software, I saw somewhere there are two flavors of vag-com? One for earlier models and one for later models...I need to find out if the registered software and this obd2 plug I got from Greg(www.lubespecialist.com) will look at a newer model like yours...we'll see. Good luck at Cable (crosses fingers and toes)

Took it in to Cable yesterday pm around 1:15 and haven't heard a word. The service rep sat behind the wheel and had no trouble experiencing the problem.

It is now 9:30 am, day two. Will keep y'all posted.

Thanks for your posts.

Just an update. Cable ordered a new juel injection pump yesterday and is installing it as we speak.

Results to follow!

Great Schools of Halibut!!! I wondered what that howl of agony was this morning...it was the service manager making the decision (chortling). Dang, brand new pump...you won't need to drive to Yukon, then /images/graemlins/smile.gif...i'm going down to fill up at Koch's today before the yuk gets here. Keep me posted.

Uh...that was lightwave who told me about Koch's Commercial Gold at 1350 Exchange, sorry. /images/graemlins/wink.gif i got all excited about you getting a new pump, snicker.

Dealer's service unit solved and corrected the problem under warranty by replacing injection pump.

Two of the cylinders were getting less fuel (fuel pressure test).

To solve the issue, they inspected for harness problems, found none, removed injectors, no problems found, performed compression test on all cylinders, correct compression, and then checked fuel pressure.

Thanks for everyone's advice, without which I wouldn't have been as dogged with the dealer's sevice people.

Hey, glad to hear it /images/graemlins/smile.gif. I know they breathed a sigh of relief when mine rolled over 100k, snicker. I think you and I and lightwave need to meet for lunch someplace and compare war stories.

Sounds good