Mitsubishi Repair: idle problems, valve engine, computer one

Question
my 1992 eagle gtx 2000 with a mitsubishi dohc, 16 valve engine will start to rev and then let off after the engine warms up like your hitting the gas and letting off all the time quickly. Is this a sensor problem and if it is can it be cleaned or tested anyway as its a rare engine and parts are expensive and hard to find. It does this all the time when engine has warmed up on a fast drive. any other things I could do myself or check. spark plugs have been replaced and new fuel filter and air filter already.It ran like a rocket for about 4-5 weeks after this was done, then started to idle like crap again.

Thanks Mike

Answer
Mike: Hate to be the one to tell you about this, but Mitsubishi farmed out the building of their computers to another company. That company did not build very good ones, in that a piece will start to leak into the computer and with time it kills off the computer. One of things that sometimes happens in the car, would be this rev. You need to get the computer coded that is in your car, most places will do this. Could be a weak or bad sensor too. But I fear it is one of those bad computers, as your car is ther right year for this. Hope this helps and good luck! Linda