A little after I do a motor swap I get a new problem. I just swapped my old 91 Lesabre'* motor in this car, and it works good. Had a few minor difficulties as these motors are slightly different.

Now, I'm noticing that sometimes when I start it, it stumbles, and dies right away when its cold. This is right away. I did this a few times till it stumbled and ran. I did not apply throttle while doing this. I also noticed a puff of smoke comming out of the exhaust. It does clear up quick and smells normal. Once the engine is running for a bit, it has no problem starting and running, even when I leave it for a little while. I'm going to see what its like tomorrow morning.

Last time I had a similar problem, it was the MAF sensor, but that made the engine not run at all unless you held the throttle open a little bit. Release it, and it died!

I can figure this out i'm sure. The car runs good while driving and does not stall at all. My first thought was a leaky injector or maybe the ECT It could also be the MAF, then again, theres the smoke that came out this morning, and it seems like its dumping too much gas in the motor!

You will want to check your ECT, and IAT, also check the EGR for a stuck pintle (stuck open) as well as cracked EGR tube.

A dirty throttle body caused the IAC passage to get clogged up on mine and I had the same problem you did, once it was warmed up it went away so I pulled the TB and used a bottle of cleaner from Autozone and it all went away

It hasn't happened again. Wierd.. I've got to find a way to get the shop scantool hooked up to this thing.
Thanks!

The intermittent problems are a real pain. But if it happens again, you do have a place to start looking.