Shop owner drove nut's by a Grand Am

[wrenchead3]

I run my own automotive repair shop and have for years. I have been dealing with driveability problems for most of my time which is why I said " No problem , bring it in, we can fix it". Well, I have a 95 Grand Am 2.3 Quad 16 V. The customer replaced the engine and couldn't get it started. I am now the 4th shop that this car has been towed to. I have checked all sensors and relays at the components and pinned at the ECM. I have an injector pulse if 1 & 4 injectors are plugged in and 2 & 3 are not, and the oppisite as well. If 1,2 or3, and 4 are plugged in I lose the pulse. When I say I have checked it all I mean it. He has also replaced most of the sensors himself. he even went as far as to replace all the ground terminals. This is drivin me nuts. I,m losing my pulse over the lost pulse.