My 1994 ford F150 XLT 5.0 has a high Idle problem that just recently showed up. The truck had been acting just fine until one day while hauling off limbs – the idle just jumped up. This is a standard shift truck – so the high idle was very noticeable during the shifts (sorry I don’t Have a tach so I don’t know the rpms) but it defiantly wasn’t racing rpms – by very high for an idle. When the ignition is turned off the and the truck restarted – everything is normal – the idle is where it is supposed to be – until I step on the gas pedal and raise the rpms, the high idle appears (doesn’t matter whether the engine is hot or cold). Sometimes it happens immediately and then sometimes it appears after a few shifts. Even it has disappeared at times when I am driving the truck only to reappear later. Got any Ideas as to the cause? I'm really lovin' this old truck and I want to keep at it's best