93 Ranger Need HELP!!!!

[OkieOutlaw]

I have a 93 Ford Ranger with the 4.0 liter engine and desperately need help. I have already replaced plug wires, plugs, and the Mass airflow sensor so those tips wont help me. The engine is running extremely rich and fouling plugs badly. I can disconnect the throttle position control module and engine idles flawlessly but as soon as I hook it back up the idle changes and within a minute or so you can hear a change and the engine goes to running rich and smoking badly. Any tips on what might be causing this?

 

[MrShorty]

1st thing I'd probably do is pull codes (even if the CEL is not coming on).

2nd thing I'd probably do would be to test the TPS. It's a basic potentiometer, so it is pretty easy to test with a DVOM and a wiring diagram.

Then I'd probably put a fuel pressure gauge on it and make sure fuel delivery looks normal.