Today for the first time ever after a cold start engine revved to about 2 - 3000 rpm and dropped to normal in a few seconds. Now, for the first time ever while driving, the throttle seems to have mind of it's own and accelerates and then decelerates ever so often but not strongly. Anyone know why this may have started? Or how to diagnose? Your consideration will be appreciated.

 

Is the fluid in the cooling system full? Also check for cracks in Vacuum lines, I do it with carb cleaner, while the engine is running spray around all Vacuum lines an connections, If the idle changes you have a vacuum leak.
Also read up on your temperature pressure sensor and how to test it. It should be near the upper radiator hose where it meets the engine on the head. There are two sensors there, one is your Temp pressure sensor and the other for temp gauge.