I just put a 3.4L in my 89 camaro rs in place of the 2.8L. I can get the new engine to start but it idles at around 2000 rpm's and if i give it gas it cuts out. I tried the timing and it was fine. all the vacuum lines are hooked up correctly and the plugs are new. I can't figure out what the problem may be. Any suggestions?

Maybe a bad EGR??? Maybe the computer needs a little time and ignition cycles to relearn. Can you give it gas easy? How many times have you started it and how long have you let it idle?

I can give it gas easy up to a certain point. I've had it running about 5 times letting it idle for about 5-10 minutes at a time.

If you can drive it try to do that. Just don't go far. My brother has a 90 with a 3.1 MPFI and he says any time he has the battery disconected he has to go through a few drive cycles before it relearns. Did you have this problem before?

No but what you're saying makes alot of sense. I'll give it a try.
Thanks

You may consider changing the MEMCAL chip with one calibrated for a 3.4 engine. About $60 from GM.