I have a 79 trailfire and it sometimes dosn't accelerate as fast as it should. It goes really slow then speeds up and runs fire. other times it just takes off fast and runs fine. also sometimes when you get it up to 60mph it will act like someone turned off the engine and will slow down to about 40 then pick up again to 60 and repeat. other times it will stay at 60 for ever and ever.