I have read up on what i think is a solution to my problem. I have a '99 GC Ltd & I get a surge in rpm from about 600 to 1200 frequently during idle, and also occasionally while driving.

To start i'm looking to change the tps, but understand if i check it or change it, that the "diagnostic codes need to be cleared" before i restart the engine.

How do i clear the diagnostic code? It says to use a scan tool, but i don't have that tool. Do i unplug the battery terminal, or will the computer just reset it? If i unplug the battery, am i causing anything else to go wrong?

Thanks for the help.

If I remember correctly, if you don't have a scan tool to reset the code, the code will reset after x number of starts. 50 seems to ring a bell....

Just disconnect the battery and reconnect.