2000 jetta stuttering at constant speed

volksman1950

Well-known member
Joined
Sep 23, 2007
Location
Basking Ridge, NJ
TDI
2000 A4 Jetta
I have a 2000 Jetta TDI with 300k miles on it that starts to stutter at constant speeds usually around 60 to 65 mph but ut smooths out as I accelerate. I sprayed MAF cleaner in the MAF thinking this might be the problem but it did not help. There is no check engine light. I never cleaned my snow screen in the 11 years I owned the car. Is this the filter at the beginning of the air intake? Could this be the problem?
 

rackaracka

Veteran Member
Joined
Nov 15, 2001
Location
Monroe, NJ
Could be air restriction, could be fuel filter, could be MAF, could be the IP, could be the IQ setting, could be the turbo starting to leak oil into the intact tract, could be electrical, could be an injector sticking.

Is this car a 5 Speed or an Auto? How's the idle? Any fault codes? What is the IQ measurement and how is the static timing set?
 

volksman1950

Well-known member
Joined
Sep 23, 2007
Location
Basking Ridge, NJ
TDI
2000 A4 Jetta
Car is a 5 speed, Idle at 900-100 rpm and is steady no problem, No fault codes (ie check light did not come on), Don't know what IQ is or that the static timing needs to be set.
 

rackaracka

Veteran Member
Joined
Nov 15, 2001
Location
Monroe, NJ
Do you have access to VCDS? If so, you may want to log the Actual vs. Specified MAF (check airflow) log MAP Sensor readings when this is happening (checking boost), log IQ and RPM.

Try the cruise control... Does the same stutterring exist with cruise active? I've resolved similar issues that were intermittant. A bad solder connection on the quantity adjuster in the injection pump (a rebuilt 11MM IP from a VW Dealer) and a dual mass flywheel showing early signs of failure can cause this type of issue.

The DMF failure created an erratic idle, intermittantly - almost like slow down shudder symptoms.
 

volksman1950

Well-known member
Joined
Sep 23, 2007
Location
Basking Ridge, NJ
TDI
2000 A4 Jetta
I have a VAG COM that hooks up to PC but only used it to diagnose CEL. I'll read up on this. I quess I have to drive the car with the PC hooked up and check the MAF air flow and from what you are saying there are separate diagnostic tests to test this plus boost, Injection Quality, at different RPM's. It still studders with cruise control on but smooths out as I accelerate. Seems to only happen at constant speed. I have had starter grinding when starting car for awhile. I hope this did not contribute to the flywheel issue you are referring to. Also have some rattling noise that sounds like a loose heat sheild but could not find anything loose.

Thanks for help.
 

red2002

Well-known member
Joined
Dec 5, 2009
Location
Grand Forks BC
TDI
2002 Jetta TDI
My 2002 jetta has developed a slight stutter under load, especially noticeable going up hills. Have not quite figured it out yet as it comes and goes.
 

volksman1950

Well-known member
Joined
Sep 23, 2007
Location
Basking Ridge, NJ
TDI
2000 A4 Jetta
What is an EGR cooler leak? I forgot to mention that I have a very slight coolant leak that I never located. I just add some coolant every month or so, it is that slow. Also my tempperature gauge never goes to 190 degerees anymore. Only goes about a 1/4 of the gauge. Could this be an issue? Is this a bad thermostadt?
 

diesel_climber1

Veteran Member
Joined
Oct 24, 2004
Location
Denver, Colorado
TDI
06.5 TDI Package II, Blue on Black. 01 TDI GLS baltic green (RIP), 2011 BMW 335d M
I'm not sure about the thermostat, but an EGR coolant leak leaks your boost pressure until the gate closes. Once the gate closes you're not longer loosing boost pressure, causing the car to "jolt" forward. Typically occurs around 2500 to 2800 rpm.
 
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