The weirdest thing happened to my Bonneville. The pintle for the Idle Air Control Valve got sucked into the cylinder and shattered my piston. It ran for like 5 seconds and the rod and pin tore up my cylinder walls.

I got a junkyard motor from a 03 SSEi with 90k on it. everything looked good, so I did the oil change and put new plugs in it. After getting it into my car it wouldn't start directly, meaning I had to give it a little gas and it would start, but as soon as I let off the gas it dies. I went with the simplest of remedies first and swapped my old throttle body with a new IAC valve in it and the problem persisted. I then swapped the coil pack from my old engine and still no change. What other things could it be. I'm assuming injectors, fuel pressure regulator or a vacuum leak. Any one else have any suggestions. I'm working on this alone, so it'* tough to troubleshoot seeing that when I let off the gas to look under the hood it dies lol. Thanks in advance, I'd be pulling my hair out if I didn't shave my head!

Forgot to mention that it hasn't thrown any codes yet either and that my oil pressure is pegged at 120, which I'm assuming is a bad sending unit. Not getting any engine noise when running so I know I have pressure.

Well, could be a number of things. But swapping the throttle body and all the sensors removes some of them. Could be the injectors. But I would test the fuel pressure first. If that'* in the 45psi range that'* good. I would pull the plugs and inspect them. You could try swapping in your old injectors in case the new ones are a different size. That would throw off the tuning. Could be a bad PCV valve, or a stuck EGR. These are all easy to deal with, simply take them off your old engine and put them on your new engine. Remember, you have a big pile of spare parts. Swapnostics is easy that way.

Thanks for the quick reply. I'm at work right now, but when I go home for lunch I will check out the PCV and EGR. I don't have a fuel pressure tester and remember the last time I needed one I got it from autozone for a $150 deposit. I might just try and buy one so I don't have to go through that anymore. I had my PCM done at intense (I only live about 10 minutes from there) and it was programmed for my 3.5 pulley and my new motor has a 3.8. Not sure if that makes a difference, but I thought I would throw that out there.

After doing some research does anyone think it'* possible that I need a Case learn? I used the new motor with my old PCM and from what I have read that means I need to have it done. Does this sound right? Could it be causing the non-idle problem?

Check your IAC wires, i had a condition once similar to yours. I took the iac out and it was pushed forward all the way, i pressed it in (allowing air to flow) and left the IAC unhooked and it ran with a high idle. As soon as i plugged the iac back in it pressed the valve closed and killed the car. Apparently one of the wires was cut and it made the IAC valve close but not open. Might be something to think about.

A car needing a case learn usually sets off an SES light, but regardless if the light is on or not, you should get it scanned with someone that has a tuner. I've seen codes come up on cars that had no SES light present, and a case learn takes all of 10-15 seconds.

An IAC pintle got past the seat of the TB... very odd as I thought it was larger than the seat.

Anyhow.. the pcm probably forgot where idle is. I've seen this a bunch of times and even on my own cars that I run daily. Fire it up and with your left foot hold the brake, right foot to keep it running. Put it in gear and hold the RPM at about 1,000 for a full minute. Try to let it idle, it if won't, hold it at 1,000 another couple minutes and you should have success.

If that doesn't work, did you swap your maf onto the new engine? This is most likely something that occurred in the swap, double check your grounds at the front trans bolt and by the coil pack etc.