CEL is on in the car (90, S5, N/A, all emissions) I read the code and I believe it to be a trailing coil. Yet the coils are in spec and the tach still works. The light comes on with KO then stays off for two seconds and comes back on and stays on. If I am reading this right it is a 01-trailing coil?? It's been driving me crazy, last time this happened I had to replace the ECU.
Anybody have any ideas??

 

To check the CEL codes in an S5, first ground the initial set connector. It's a green single pin connector in front of the driver's side strut tower. Just stick a piece of wire in it and ground it off to the car's body somewhere. Then turn on the key and watch the CEL light. If there are codes stored it will flash them in sequence using a long flash for 10's and a short flash for 1's . So a long flash followed by two short ones would be code 12. If there is more than one code stored, additional code sequences will be flashed after a short pause.

 

I know that, I've been over it again and again, BUT it does the same thing. Ground the connector and then KO(key on) and cel goes off for two seconds and back on=no blinks... I've cleared the code and it still comes back when I drive the car. When I drive the car and it would warm up it would cut out and run like crap, when it was cold it would run fine. Now it runs like crap in general, hesitation, backfiring, WOT(wide open throttle) has no power. TPS-good, afm-good, new plugs-may change do to flooding issue this morning, coil packs L&T-good, fuel filter-good. As for the fuel pump and OMP?? haven't gotten to those. The car was doing fine until Sevenstock10. Once the CEL pops up it runs like crap, problem was intermitent; now the CEL is always on.