88 ram 5.2 TBI

I bought this truck yesterday. This truck has been in various shops in the county but still not fixed.
The problem- The engine lopes at idle, and at half throtle. Full throttle it will clear on out.
I checked the tps. Its okay. Checked fuel pressure. Its okay.
New parts that have been put on it-
fuel pump, ecm, oxygen sensor, distributor pieces, etc...
When running I unplug the map sensor, it stops loping but runs very rich.
The map sensor has not been replaced. I havent tested that sensor yet because I dont have a vacuum tool.
What I am asking, Has anyone came upon a faulty map that has these symptoms. Thanks