[s-cars] 1995.5 S6 now running rough after warm up

[Jeff Postupack]

Gents.

My old trusty winter  Blk/Blk S6 is now suffering in the barn.  157K miles
Stage 1, stock all else

I do try to keep up on preventative maintenance, but I may have
procrastinated too long on one particular item.

After a near flawless 720 run NH to PA- NH last weekend, it developed a
misfire under boost around Jan 14th  It got worse and worse, until it was
easy to debug on Thursday.

I isolated that pb to a single Bosch spark plug, however I changed them all
to new NGK BK7RE. being suspicious (The Bosch I removed were the
tri-electrode, forgot the P/N)

After plug swap it ran strong up until Sat morning.. when it started
running so rough that I would not drive it up my hilly driveway, back in
the barh she goes.
(Sat am cold start, after warm-up rough idle and very low power, stumblinjg)

Code is
 00537 VAG1551/2 Fault Code Number- See below C/O QW

After checking my records, I changed the easy stuff this morn.
new fuel filter
new Fuel regulator
New Oxygen sensor.

After each component change I cleared codes and ran again.
00537 re-activates.


This brings me to the last one you guys may say is obvious, Fuel Pump.
I don't have records on this being changed..Hard to believe but..


QshipQ? , Dave Dawson? All takers?

Go ahead, beat me up for not changing the FP, but HELL! It's January in NH!


Jeff Posto

Oxygen Sensor Control Limit exceeded,
fuel pressure too low or too high,
 intake or exhaust leak,
 defective ignition system component,
 intake air leak after air mass sensor,
O2 sensor is faulty

Symptom: CO before catalyst is below 0.3% or greater than 1.0%, Extremely
lean or overly rich exhaust, Spark Plug foulin