possible fuel injector problem on 1991 Ford Ranger

was driving one night at about 35 mph then the engine just revved up real high. tapping on the gas pedal didn't make a difference. turned the truck on and off several times to and it finally slowed down on it's own. that was 6 weeks ago. now it is doing it again, but nothing is making a difference. Have replace the mass air flow sensor which had a broken wire and have tried a fuel injector cleaner additive. My friend thinks it might be the fuel injector stuck open, but he knows nothing about cars.

Asked by for the 1991 Ford Ranger
One time i had a customers Ford taurus do that to me. after many thoughts and ideas about what it was i discoverd that the clip that holds the cruise control cable to the throttle control lever on the intake had broke and once in a great while it would get jam the throttle open and then eventually work loose . check to see if its still connected to the throttle lever on the intake
thank you, I do know that the throttle is not stuck. I have checked that... also I think I ruled out the fuel injector and throttle because when the air flow sensor is hooked up then it revs high, when unhooked it won't stay idling. that tells me that the throttle is not open and the fuel injector is not forcing fuel through. I hope that makes sense. I don't have cruise control or anything... not even a radio. all manual. Gonna check all wires and connections tomorrow for corrosion. The truck spent 18 years on the Oregon coast.