Driving to work this morning I noticed my car was running rough at 3k rpm's and was hesitating a bit. After about 15 minutes it got really bad and I was losing power and the check engine light was flashing on and off. It felt as if the car was misfiring. I was able to get to my office. Right now the car is beiing towed to the dealer. Last night I installed new sport cats and did a road test and it was fine. Anyone have any thoughts of what the issue could be?

 

First guesses are throttle position sensor or MAF.

 

It sounds like a problem I had on my C4. It turned out to be a bad coil pack. Took two dealers to figure that out!

 

I had an issue with mine, however it wasn't as prevelant as what you described...turned out the ECU needed re-mapping. According to the service guy the ECU "lost" it's programming...

 

Electrics....that's where you'll find the gremlin. Let us know what you hear after they hook up the hammer.

 

what kind of sport cats did you install?

 

NJ-GT is on the right track...quite possible your "sport" cats put the car in limp mode...too coincidental to be much else...good luck

 

The dealer called me late friday to say that three of the cylinders were misfiring but did not have anymore time to look at it. I will find out more on Monday. The sport cats in installed were from Fabspeed. I called them to see if it was coincidental that I had this issue right after the install and they said they have never heard of that happening.

 

I had the exact same problem on my GT3. It turned out to be part of the variocam system that had one bank of cams off timing. I think the variocam adjuster was "hard over" one way. They replaced one hydraulic part and it's worked fine since. Good luck.