I have a 95 Nissan Pickup and when it is idling it revs up and then goes back to idle revs up goes back. I'm would like to know what this might be any help leading towards it would be great... Thank You

Check the procedure for adjusting your idle speed. Frequently, you warm up your vehicle, disconnect the idle air control connector from the IAC valve, and adjust the idle speed with a tachometer to factory specs. Tach attaches to a wire, often blue, coming from the igniter in the distributor. Sometimes, the adjustment screw is "leaded in" on the throttle body to keep you from messing with it. After the idle speed is adjusted, reattach the IAC connector to the IAC valve.

I have heard of similar problems also being caused by a bad igniter. Go over the electrical system and make sure everything is in good shape.

Mass Air Flow Sensor. Located In The Fresh Air Intake Passage Somewhere. Don't Know Exactly Where In That Application Though. Check For A Grid Or A Tube With Grid In It. This Will Have Wires Running To It Also.[between The Throttle Plate And The Air Filter]

Other possible causes are a failing heated oxygen sensor (HO2S), which regulates fuel injection duration; a dirty Idle Air Control (IAC) Valve; and an igniter (ICM) that is breaking down.