Ford E-150 Problem Report
Ford E-150 Engine Idle Rolls Up and Down
If engine idle rolls up and down, and diagnosis rules out Idle Air Control (IAC) valve issues and vacuum leaks, the Programmable Speedometer/Odometer Module (PSOM) can be at fault electronically. The instrument cluster will need to be replaced, the PSOM is inside the cluster.
The engine would randomly 'race' without warning. I would have to keep foot on brake at stoplights etc. to keep it from 'jumping out' into traffic. We tried vacuum hoses, egr valve. Doing it again. - lmagill
Sludge build up on the throttle plate and/or idle air control valve can cause a poor engine idl...
my ford van when driving down the road at high way speed,it will jerk in and out like its cutti...