92 f150 302 5 speed. Symptoms are high idle when in neutral, almost shuts off when I let the clutch out in gear to take of from stop, when driving and push clutch to shift gears the idle shoots up to 3000 or so and sticks until I put it in gear and let clutch out. Really the idle is all over the place. So far it has new plugs, new wires, new coil (all before these symptoms), new o2 sensor, new tps, ran codes and I believe it said the left bank was lean? Not sure what that really means. My uncle is a mechanic and he's helped me through this, but I've been to busy to fool with the truck. Would like some more things that I should look for if anyone could help. Thanks

 

It could be the IAC valve.

 

Where is the iac valve located

 

Have you run codes to see if anything is out of order?.

 

I've got the same motor and have similar problems. What helped my idle surge issue was switching out all my vac lines from the intake manifold to the fuel pressure regulator, a/c, to and from the coffee can. My red line to the coffee can/vac reservior literally broke in my hand.

If you figure out the stalling when letting out the clutch, I'd love to know the fix!

 

The IAC is on the drivers side of the throttle body. Take it off, spray with carb cleaner, and clean with an old toothbrush

 

Throttle body cleaner, don't user carb cleaner in anything but a carburetor.

 

Will have to run codes again to refresh my memory on what came up. Pretty sure it said left bank was lean. Not to sure what that means. Guessing that could be caused by a couple things, that's why I replace the o2 sensor and tps. While I wait for my uncle to get some time to run codes I will check iac valve

 

Took iac valve off cleaned it the best I could. Thought it was running better, started to hiccup a little as it warmed up, there went positive thoughts. Went and tapped the accelerator and there she goes. Idle stuck where it stopped and sat there for a couple seconds, then back down, back up, and so on. Seems to me that the engine doesn't know how to run. So it's guessing where to idle and when to do other things. As far as codes go I don't think the CPU gave much info on problems. Just led to fixing all things that cause the vague code that came up. O2 sensor, vacuum lines, tps, iac valve, and I'm sure there are other things. My uncle told me last time he fooled with it that he was thinking either the wiring from the tps to the CPU was fried or the CPU itself. CPU is fine, I pulled it and checked and it looks brand new inside. Could the wiring from the tps be the problem?

I know that's a lot to read but I just want to figure this out

 

Get the codes, the PCM doesn't "guess", it reads values. The sensors usually send voltage values which should be in an acceptable range, if they're out of said range for any sensor the engine starts running rough.

 

Silly question but what kind of TPS did you buy? Where from? (I got a BDW brand did from Advanced Auto)