Oldsmobile/Buick Repair: 88 century 2.5 4 cyl, main bearings, throttlebody

Question
  I have just put a crank kit in this 2.5 4 cyl engine. It had a spun rod bearing so I had the crank turned and used the right size rod and main bearings. I got the enigine back into the car, got all wiring connectors and vacumn lines hooked up now. It starts but when the computer starts to drop the idle back down after start-up, the engine dies. If I rev it up it will run fine but as soon as I let off the gas, it dies. There are no codes and the check engine light is off. Any idea of what I might be missing here?

Answer
hi john..hmmm the prob really sounds like a vacum leak check all of gaskets that can leak vacum,(intake to head gasket) base gasket) under throttlebody)after you check for a vacum leak at these points and are positive they are sealed and the right gaskets and installed properly..if all this is ok.check the idle air control sensor make surethere is no carbon inside the valve.here is another common prob i have ran into if all the other stuff i just told you don,t help.remove the valve cover loosen the rockers run eng adjust rockers tighten and loosen until you can tighten all the way downthe 2.5 has a little trouble getting the lifters to prime after long periods of being dissassembled.this procedure however a little messy from oil is usually effective.if none of this works write back we will dig further.ty and please take time to rate my answer .it is important to us  billymac