Warm idle sporratic behavior

[Jrock909]

What causes a SD 302 motor to hunt for idle when warmed up? I have replaced the ACT, IAC valve, O2 sensor and it still hunts for idle on my 92 F-150 Truck? Does the Pcm have to match the camshaft and everything else? Where does the orange ground wire come out of on the engine harness?

 

[HISSIN50]

How does it hunt? Just a general wandering or only at certain times (rolling, stopped, etc)?
Does it change if the AC is on?
Any codes?

A diminished vac signal at idle can cause issues (pertaining to a possible cam).

Are you talkin about the O2 heater ground? It's at the back of the intake as I recall.

Good luck.

 

[jrichker]

See "Help me create the Surging Idle Checklist" at http://forums.stangnet.com/showthread.php?t=698148
for help with your idle problems. The first post contains all the updates to the fixes. I continue to update it as more people post fixes or ask questions.