Re: Finding/Reading "Check Engine" codes

[Bfuson@aol.com]

I've encountered similar problems with a '92 S4.  Usually happens when
hitting idle after running for a while at Freeway speeds (plus ..... just a
little :-) ).  The light comes on almost immediately once the engine
approaches idle, remains on at idle,  goes out as I pull away, usually
remains out until the next stop.  Sometimes this process continues for quite
a while, other times it happens just the one time. 

As you noted, I've never had other problem indications (rough idle, rising
Oil temp, decreasing Oil pressure....).

I've had the codes checked multiple times and the readings have always been
normal ( except for one time when the code generated was supposedly invalid
for my car?).

Now the fun - it only happens when I run Sunoco ULTRA 94.  Never happens with
Shell or Marathon.  I've been told it also occurs with BP, but haven't tried
BP on this car.

I never had the problem on my previous TQ ('89 200Q), but according to the
dealer the problem is common with the 20v Turbo I5's.  

HTH, Bill Fuson