I got in my car today to do some final work before tomorrow i ship it to the person who bought it. WEll, i got it, turned it on, and the tach worked fine, then i started driving and at just over 1,000 RPMS the needle stopped for a minute, then went up, but after that it begcame really jittery, moving very slowly with the RPMS of the engine, sometimes skipping ahead, sometimes jerking, then finally it got stuck at 2,000 RPMS and it wont go back down or move or anything, its stuck there! it even stays there when you shut of the car! how can i fix this!? please help.