Breaking up
 

Is it possible that a TPS can cause an LT1 to break up at lower RPM's? The car doesn't do it unless it is 1) warmed up all the way and going into closed loop or 2) is really hot outside no matter how long it has sat. So I changed the ICM thinking it was breaking down when it got hot, and it's fixed a little but still breaking up bad. Now I haven't had a chance to run the codes yet but if I hold the throttle in a certain place, I can trigger the SES, let off the gas or increase it a little bit and the light goes out. When the SES is on, the car runs pretty good. I'm hoping it's not the opti, but a local hot rod shop has opti's in stock at a decent price (they normally don't carry junk) but before buying an opti, I wanted to get some opinions on the TPS.

Re: Breaking up
 

Hook a scanner up and monitor the TPS values as you press the pedal from 0-100%

Any hangs or skips show a faulty TPS. Might want to look into the LT1 IGN module spacer mod. Its just a few washers under the mounting bolts to get it off the cyl head

Re: Breaking up
 

From what the codes show I've got one o2 that's running lean, and it's showing a MAF fault (don't know if that is from where I unplugged it last week or not for a bit to test). I'm going to throw a stock tune on it set to SD mode to eliminate the MAF and check with my scanner to see the TPS values, I looked at it yesterday with it running...duh you can check from 0-100% with the car running, but the spark advance was showing great...up to 45* advanced...sitting at 25* at idle.

Re: Breaking up
 

You can test the TPS with the car off. I do not advise watching the scanner as you slowly go from 0-100% throttle while moving

Re: Breaking up
 

Yeah, I ment that you can't really check with it running (was sitting in the driveway). I'll go from there and see what happens, thanks again Pocket.

Re: Breaking up
 

Well, looks like the MAF took a dump. Set my tune to a SD setup and it's running just fine now. Guess I'll be searching around for a new MAF and hopefully running it in SD won't affect my gas milage too much.