Conversation Between Kemicalburns and szealuss

Update to the swap-- I got a 46,000 mile 95 mustang motor.

Took it down to a long block and added new oil pump and timing chain and swapped all the EFI from the original truck. Put everything back together just like I pulled it. It's in and is very hard to start have to hold it wide open to get it to fire. Then it seems to run fine--then it runs rough-- now it is almost impossible to start--and then it will start. WTF.

I have run any diagnostic on it --I did double back and check all my sensors and they are all connected. Everything is exactly like it was New. Except it doesn't run right. Any ideas? Do i have to reset something? MAP sensor-fast idle sensor? Any help much appreciated. THANX