Hi everyone,

I've been searching the forums for a bit now but I have the following problem in a 2003 a4 1.8tq

A week ago the CEL came one, care was running fine, actually put on about 1600 miles since. Got a Vag-com scanner and scanned it yesterday and got two codes: running lean And long term trim (more fuel). I decided to clear the codes to see if they would re-trigger.

Next thing I start the car and now the car idles really rough ~600-900 rpm sputtering and the CEL is now blinking. I re-read the codes and now all i have are 5 misfire codes (one per cylinder).

Above 2000 rpm everything smoothes out and the car seems to drive normally, only problem exists at idle.

SO i've searched around and figure the following:

1) MAF - at WOT @6000rpm the most I got was 130g/s
2) Vacum leak ?
3) Coil packs?
4) Pre cat O2 sensor

also - could clearing the codes cause this misfire problem, i only thought that it would simply clear the memory ??

Gonnna start by cleanning the MAF, any input would be really helpful

thanks

 

usually blinking CEL = blown coilpack(s).
but if your saying it runs fine above 2000rpms than most likely yo got a vacuum leak. but its weird.

 

Did you solve this problem? I am having similar issues.

 

thanks for the input,

So i cleaned the MAF - problem persisted although the mapping improved to ~160g/s @wot ~6000rpm

So I spent many hours under the hood and finally found the problem. It was a cracked two-way valve in the vacum system in the middle of the engine toward the windshield below the manifold just to the right of where the fuel line runs in (whole bunch of vacum connectors/lines there). Temporarily re-connected the valve with duct tape, restarted, cleared the codes ... runs great, no CEL, smooth idle...

Will probablly replace the part some time this week.

good luch with your car.

 

this part?

 

yup that looks like it, although mine broke off at one of the nipples

 

thats a common thing that brakes

 

Edit.