Relentless Revving

I've got an '01 Rav4, manual tranny with 280,000 miles, and when I start it up anytime, the engine revs itself up to around 2,000 rpms continously from 1,000 to 2,000 repetatively every two seconds. I thought this was just the engine trying to warm up but it does this even whilst driving and the temp gauge is right where it should be. Someone told me it could be the thermal sensor. Please help, its making for very unpleasant acceleration!

I've got an '01 Rav4, manual tranny with 280,000 miles, and when I start it up anytime, the engine revs itself up to around 2,000 rpms continously from 1,000 to 2,000 repetatively every two seconds. I thought this was just the engine trying to warm up but it does this even whilst driving and the temp gauge is right where it should be. Someone told me it could be the thermal sensor. Please help, its making for very unpleasant acceleration!
Thats a LOT of miles bro. Check the spark plugs and wires. Most likely sometihng in the Ignition system. Could be the trans starting to go out on ya