I cracked the block in my 1992 F-150 302 manual NITE. I bought a long block from autozone. I had the engine installed at a local exxon. I didn't have the time or space to do it myself. The main problem I am having is the idle. When I turn on the ac, the idle should pick up a little to compensate for the extra strain just like it used to with the old motor. Now, it drags the motor down very low. I'm amazed it keeps running at that low rpm. I took it back and found out the negative cable to the engine wasn't connected at all and the chassis to engine strap was loose! How it ran at all, I don't know. Anyway, it fried my stereo amp in the process and it still wouldn't idle right. I left it with them and told them to call me when it was ready. I have it back now. They raised the idle to compensate. The temp sensor for the gauge was bad and I replaced it and the other sensor also just in case. I probably need to replace the O2 sensor but, haven't had the chance yet. It's running better but, when I push in the clutch, the engine is revving and makes for rough shifts. Oh, I had to put in new fittings on the throttle body for the coolant. The old one blew apart on the way home. I removed all the sensors and cleaned the throttle body thoroughly before putting it back together.Does anyone know what I can do to make it idle right? I think it has the MAP sensor? It has the twin opening throttle body with the huge intake that hangs over the valve cover. Thanks in advance!

 

Have you run the codes yet?
Sounds like one of the sensors. Maybe throttle position sens.

 

 

There were no codes. I have the problem fixed though. I believe the biggest problem was the return springs. I noticed they weren't pulling the throttle back all the way and so, I added a light spring. I also replaced the o2 sensor and cleaned the idle valve. So far, it's running great. I think the spring was the big problem though.