My 93 Honda Prelude is not idling, it keep jumping from 3000 rpm to about 1000...
 

...rpm up and down, all the times? 93 honda prelude, 150K miles, manual transmission, keeps jumping from 1000s RPM to 3000s RPM up and down all the times, even when engine is already warm. When driving is normal, but when I put the gear to 0. it start jumping? please help, I need car for my jobs,,, I cant afford to bring to the shop?

If it's a bike you mean ..Ignition pin bent at all?































I had a problem with a scrambler/field bike I used to have and it would just rev like crazy automatically.































Turns out the ignition pin was bent a bit. Straightened it with pliers and it worked fine.