You didn't say which ignition system you are using. If it's the Mopar style with an ignition box (OEM/Orange/Chrome), try another "known" good one. I've seen a couple of the Chrysler style boxes act like rev limiters.

Not sure if other brand boxes can malfunction in a similar manner.

Do you recall if it started after you changed anything?
Always run 35* timing? Different brand fuel? Change plugs? (Oops, nevermind on the plugs!)

Last edited by Locomotion; 08/26/12 08:43 AM.