Jumping IQ 2.0 to 7.7 rough idle

Airsciguy

Member
Joined
Nov 18, 2006
Location
Weare, NH
TDI
1999.5 Jetta IV, 2003 Jetta IV
I'm new to this site and am not sure I'm in the right area but please bear with me. I took this car in as a poor beaten puppy and have gone thru ABS problems and other things but this idle issue is sucking the fun out of all my efforts. My 1999.5 Jetta IV ALH is a stumbling mess. I have slow coast to stop stumble with clutch in or in neutral and then will smooth out periodically at rest and then go into convulsions again. My Vag-com says my injection timing is jumping between 50 and 60 in a vertical path with the cloud thing on. IQ jumps between 2.0 and 8.0. I have the 520 nozzles. My Vag-com won't let me decrease the IQ below 32645 and if I go high it runs worse so I feel that if I could get it lower all would be grand. Should I break out the hammer and give that IP a whack? EGR vac test is good. Intake looks ok. Replaced all vacuum line and N75 valve. Runs like a bat out of hell with little smoke and get 50mpg otherwise. No faults except CD player has no comm?? New car with many problems so CD player has been low priority. If anybody has a solution to this I would really appreciate it. Dave
 

geoffap

Member
Joined
Feb 26, 2004
Location
Saint Helens, Oregon USA
TDI
Jetta '03 Silver
Rough Idle and stumble with clutch in

Airsciguy said:
I'm new to this site and am not sure I'm in the right area but please bear with me. I took this car in as a poor beaten puppy and have gone thru ABS problems and other things but this idle issue is sucking the fun out of all my efforts. My 1999.5 Jetta IV ALH is a stumbling mess. I have slow coast to stop stumble with clutch in or in neutral and then will smooth out periodically at rest and then go into convulsions again. My Vag-com says my injection timing is jumping between 50 and 60 in a vertical path with the cloud thing on. IQ jumps between 2.0 and 8.0. I have the 520 nozzles. My Vag-com won't let me decrease the IQ below 32645 and if I go high it runs worse so I feel that if I could get it lower all would be grand. Should I break out the hammer and give that IP a whack? EGR vac test is good. Intake looks ok. Replaced all vacuum line and N75 valve. Runs like a bat out of hell with little smoke and get 50mpg otherwise. No faults except CD player has no comm?? New car with many problems so CD player has been low priority. If anybody has a solution to this I would really appreciate it. Dave
Did you solve your problem?......I'm having the same type of problems on my 2003 Jetta.
 

doc_m

Top Post Dawg
Joined
Dec 2, 2002
Location
somwhere
TDI
None
wonder would dirty or aging injectors have anything to do with this or perhaps some fuel that's not the best?
 
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