Hello everyone,

I recently had to do and engine swap on a 92 f150 inline 4x4 M5OD at 153000 had so much blow it was quart for every 20 miles (i bought 5 30 weight and it cost me bad). Im no mechanic, but i was able to swap the engine with another straight six. This one was an 89 engine that i was told came out of another 92 f150. I have 6 months and unlimited miles.
Whats going on is that i have to have it at at least 1200 rpm or itll stall and about die on me at a stop. But man on the highway, it runs good.
Ive changed out the TPS, throttle body and gasket, egr valve sensor, new ignition coil, good knock sensor, distributor and rotor are good but i might just change it out too, but i still have rough idle. When i went to change out the fuel injector wiring, there was a transistor looking plug right next to the fuel pressure regulator at the fuel rail. Instead conecting to the sensor between the throttle body vacuum lines and the canistor (i dont know the name of the part, but when it plugs in it ticks sometimes, and the vac lines run though a union from the throttle body to the carbon canistor).
Anyhow, the 92 wiring was different so i had to install my original distributor to the new motor so the wiring and harness could all match. Like i mentioned, the only difference was that one connection right before the #6 injector plugged in to this transistor looking thing that says Stemco 881 61B F170 431_5040.

The round cut is where it was sitting in fuel rail with a clip, right next to the fuel regulator.

I read up on how a restirctor plate could help with the rough idle, but when i ran my truck today with the green vac hose unplugged and capped, it idled worse. I plugged it back in and still had a rough idle but didnt die. O did forget to disconnect the battery before running it unplugged so ill try again, Lord willing, tomorrow.
Hopefully someone can help me out with this. Be Blessed ya'll.