i think that my car is cursed. i have a 87 tpi 5 spd and up untill about 2 weeks ago everything with the tach and speedo where normal. in 5th 70 mph at 2250, in 4th 40 mph at 2000 and 50 mph at 2500. Now it is jumping around, 70 at 2400, 40 at 2200 50 at 2700 (at times other numbers). Also my check engine light comes on for 1 second and the car tries to stall then catches itself.

HELP
paul

 

Welcome to the boards.
sounds like a ground problem to me.
You may have a loose ground somewhere since the car isn't running right (maybe the ground strap from the engine block to the firewall).

Also check the codes in the computer. If the check engine light came on a trouble code should be stored.