After installing aftermarket heads, cam, intake, TB, etc (see signature for specifics), whenever I first start my car in the morning I make it may 1/2 mile and it starts bucking and all the idiot lights flash on the gauges sometimes go crazy and eventually the engine dies. It will do this several times before it quits and then seems to run fine. I had the car tuned by a very reputable and well known tuner. The only code it throws is a fuel code...but since it eventually runs fine I don't think it is the fuel pump, is it the computer? I know it's difficult to diagnose long distance, but maybe somebody else has run into this....thx

 

Fuel pressure is easy enough to check. Have you tried changing the fuel filter yet?

 

bad o2, some kind of intake leak, bad ground?

 

sounds like it could be some of the tables off while the car is in open loop. I would get the exact code and let us know.

 

Okay, the SE and SES lights do not stay lit after you stop and restart the car. Now, even scanning while the car is running with the SE and ASR light on (why the latter I have no idea), the scanner picks up no codes. I don't remember what the one code I picked up before was other than it was fuel related. I already tried replacing the O2 sensors and fuel filter (after the code)....All of this said, the last time I drove it (after going through the ritual of "misfiring" and restarting) it ran stronger that it ever has and even at 6500 RPM it did not seem starved for fuel. In fact it ran fine the rest of the day. I don't know whether it's coincidence or not, but I have been starting it a couple of times a day and letting it reach operation temperature and then shutting it off without driving it. That seems to help, in fact the last time when it acted up it wasn't nearly as severe of "misfire". I'd appreciate any input...

 

Im curious as well. I am having a similar issue and have yet to find out what the deal is. I did a heads cam package on my c5 and added an ls6 intake, ported TB, Ported maf, Shorty headers, CIA intake, and cat back. I also added slightly larger injectors. went from a 25 to a 28lbs injector. My car runs great at first start up but after about 2-3 min of running it starts missing and bucking. If i unplug the maf sensor it cleans up but after 30 sec. does the same thing again. Im guessing its a tune issue. Im having my tuner come wednesday to attempt to tune it and fix the issue. I tried the O2 situation thing as well. PUZZLED and FRUSTRATED!

Hope we get this figured out!