I just bought a S5 n/a 1990, with a check engine light on. Read the flash code and recieved a trailing coil pack code. So I checked resistance in the coils and they were in spec. So I decided to put on another set of coils with a new bracket to replace it fully. I drove the car and it ran good. Yet the code wouldn't clear and today it started again. I go to accelerate and the more I step on the gas the more it shutters on me like pratically leaping up and down. Yet other times it runs like a champ. I haven't replaced the wires yet and it has new plugs. Any other ideas?????

 

so know one knows damn time for round two of "figure it out myself" thank you... lol

 

Check to see if the TPS is in spec? and isn't shorting out when you press the throttle.

 

It really depends on exactly what's happening . . .

If it drives around fine, and when you put you foot in it it breaks up under hard accelleration but then goes right back to being perfectly normal without having to shut off the car then its probably in your ignition system somewhere.


If however you start her up, she purrs, then you hammer it and BAM! You stumble and sputter and seem to get into a mode where you can barely give it gas without it practically dying on you, and this condition only goes away if you shut her down and restart her . . . well then its your OMP.

If it is the latter then what's happening is when the OMP fails it throws a code and the computer goes into a limp mode until you shut down and restart. This will also throw the check engine light on. Seems to me that the 7 is one of the few cars who's check engine light isn't merely an O2 sensor light. It actually trips for lots of reasons.

Make sure you're reading ALL the codes its throwing, it threw like 5 codes at me when my OMP went bad. Its a 15 minutes fix if you've got one laying around. CHeck the shop manual, there's an easy check w/ a multimeter to diagnose a bad one.

Good luck.

 

Yes, check the TPS, then the OMP. If OMP is bad you also might need an ECU.
Good luck

 

my cats were cloged on my 88 vert which caused severe hesitation i hollowed them out and smooth power all the way to red line i dont know if in fact that is your issue but its another idea for you to check out

 

My first rx7 did this when the cats plugged up as well but I had no power what so ever. Even had a ford festiva beat me light to light. I knew then that I had a problem or that someone stuffed a v-8 in that festiva.

 

okay well I been doing some searching and some reading. Fuel filter? Injecters? AFM? TPS? So tomorrow check the TPS and replace the filter. Check resistance on AFM??? Where is the #'s on it? AS for the trailing coil code off the check engine light what to do with that??? It won't clear and the prblem is continuing. The car had been running like a raped ape until this morning. Now all day its been acting up. NO mods except a alarm that came with it and the wiring sucks!!

 

For the AFM, just follow the wire harness, and it should lead to a clip, that is where your pins should be.

I am not familiar with S5's, but I know on S4's flapper style AFM it is the way I just described.

James