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kirksaudi
04-15-2012, 04:18 PM
Hey guys I have a 99.5 A4 1.8t, My problem is once the car has been driven for and hour or so I'm getting this jerking during light accel. It only does it while city driving. Also while at idle the car shakes lightly due to rpms dropping and rising but like i said it only does this after so long of running.... No cels or anything. When I first got the car I had a misfire on cylinder 2. Changed the plugs and put a new coil in and swaped my injectors around to make sure I wasnt missing nothing and problem went away now I got this. As far as performance mods I just have a cat back system thats it for now. If you got any ideas i sure would love to hear them Im starting to scratch my head over here[facepalm]

ECS Tuning-Audi
04-16-2012, 12:41 PM
Sometimes it wont throw a CEL under light misfires. I would still have the car scanned though just to be sure. Check the connector boots on the coils for white burn marks, which would indicate they are arching off the sides of the pull well.

Jason

kirksaudi
04-19-2012, 03:41 PM
hey jason no arcs and no codes apon scan[facepalm]

avantually
04-19-2012, 08:40 PM
Have the same problem under half boost 10lbs plugs new gapped @ .028 new valve cover gasket, boots new. Next step fuel filter no codes idk???

ECS Tuning-Audi
04-20-2012, 06:42 AM
Check out the ICM. It's a pretty common part that fails and will cause misfires. It sits on top of the air box. You can check the individual pins with a multimeter. Might also want to do a boost leak test too!

Jason

kirksaudi
04-20-2012, 01:40 PM
k thanks jason. whats the best way to do a boost leak test? I've read several different ways.

ECS Tuning-Audi
04-20-2012, 01:55 PM
k thanks jason. whats the best way to do a boost leak test? I've read several different ways.

It all depends on how much time you want to spend! I've done a quick boost leak test with a tennis ball that I drilled a pencil size hole through the middle and an air gun :)

Or you can build a boost leak tester using pvc pipe, a valve stem from a bike tire, and some silicone sealer.

If you search around on this site you can find DIY threads on both.

I hope this helps!

Jason

lucaq
04-21-2012, 09:48 AM
measuring blocks 14 15 and 16 provide real time misfire counters, if you have access to a scan tool that you can take on a ride with you, you can see which cyl(s) are misfiring and then you have a better idea of where to concentrate your efforts. Jason is right that minor misfires will not kick off a persistent code, but with the measuring blocks you can still see the misfires.

kirksaudi
04-23-2012, 02:36 PM
ok are these blue tooth scan devices i see on ebay worth a damn on our audis'? Some say they work other due????? Oh yea and today i noticed just after having it on for 10 mins with the ac it starting doing the soft misfire at idle or "jumpy" idle but the car shakes evertime it "jumps"

ECS Tuning-Audi
04-24-2012, 07:31 AM
We sell a scan tool that allows you to see measuring blocks below!

Click HERE to order or for more information. (www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Tools/Scan_Tools/ES9950/?salesrep=JMarusic&utm_source=audizine&utm_medium=forum&utm_content=JMarusic&utm_campaign=postreply)
http://c1552172.r72.cf0.rackcdn.com/223951_x600.jpg (www.ecstuning.com/Audi-B5_A4-Quattro-1.8T/Tools/Scan_Tools/ES9950/?salesrep=JMarusic&utm_source=audizine&utm_medium=forum&utm_content=JMarusic&utm_campaign=postreply)

Let me know if you have any questions.

Jason