Why is my Mazda B2500 idling so high at completely random times?

I bought this truck over 4 years ago and have had this problem from day one. I have tried nearly everything, IAC valve, M Air Flow sensor, TPS switch, got tired of replacing things it could be and have just learned to deal with it. Mechanics shop provided me with no additional help after a thorough diagnosis. The problem occurs at totally random times, no pattern whatsoever. Sometimes, it will happen when its cold, sometimes warm, seems the worst when I am running the A/C where the idle will exceed 2500, sometimes 3000 with the clutch depressed. The other times I find it shooting up to 1500 to 2000 while approaching a stop sign in neutral for example. The only thing I have found that will help with the problem is to turn the ignition off and back on rather quick like while I'm heading down the road at any speed, which I am uming is resetting the computer and helping, for a little while at least(maybe 5 minutes depending on when it decides to do it again). After resetting, I approach a stop sign and the final seconds of sopping the brake pedal does a strange "click" once or twice, don't know if that has anything to do with it, probably more to do with the resetting of the computer. Whatever it is, is has something to with a sensor relating to speed, as this does not occur while at a dead stop, any advice would be appreciated, as it is prematurely wearing down my pilot bearing AND my brakes.