weird problem, cel
 

hello, 4days ago i intalled a gmpp exhaust manifold,gmpp performance exhaust, pro-thane tranny mounts and half of stage 2. I had GM do the pulley and the program.

It was running really well, love it. But yesterday was the first time driving in the rain. My throttle seams to stumble off idle and kind of jars the car then seams to smooth out. But the power seams much less now and the boost builds up much faster and effortlessly. I wonder if it is a problem with my stock cat?. 06ss/sc. 18,000 miles on it. Any ideas?.

What code are you throwing?

It could be your catalytic converter. Mine went out at around 20k and it was clogged so bad I couldn't get over 4-5k on the tac. Also the exhaust was quiet again like I was back to stock.

I took it in and had it replaced under warranty and bam, back in business.

Did you install the pulley and reflash but not the injectors, if thats the case it's probably related to that. The PCM is added significantly less fuel than your motor needs because it thinks you have larger injectors.

yeah, if you didn't get the injectors in there on that tune, thats gonna be dangerous. It would have been safer to install the injectors first and run too rich and then get the tune

I have no idea what code it is.

And I did put the injectors in prior to the tune. If its the cat then I suppose warranty will handle it?

I unplugged the batt today to reset the code. We'll see if it comes back. I guess I should also get a different kind of spark plug for my stage 2 but I have no idea what the different plugs do. :-(