Ok i have an 88 se and i just change my engine because my rear seal went out. The engine starts but wont stay running. It will stay running if i give it gas but only over 2000 rpm if i let it go lower than that it runs rough and shuts down. I checked all the vacumn lines and they appear to be right. Th engiine was working fine in my friends car. Any help would be great, I've been working on this thing for the past three days.

 

Sounds like the problem I had on an 86. On the back of the fuel injection stuff, way down in behind everything, there's a vacuum port, a big one. If it's open, cap it. I would say your problem is deffinately vacuum.

 

When you mean injection stuff do you mean the fuel injectors?
can you be more specific on the location. This is driving me crazy.