so i have a 99 civic with a stock ls block stock gsr head ebay turbo 440 cc injestors ecu socketed tuned on unknown program. car came this way everything running fine then i blew my motor had custom car care put a new block and head in the car exact same setup no changes whatsoever to parts list. now when the car is at idle has a very fast surge, and i have no partial throttle. if im not accelerating im decelerating. when i try to hold the car at a steady speed in any gear it just jumps and studders. please help very annoying issue thanks.

 

Why haven't you brought it back there if they did the block and head install? Doesn't sound like anything serious, probably just a bad sensor or bad wiring from the original swap. Or a block and head that isn't compatible with whatever unkown tune you have.

 

i have tried taking it back they say i need a wire harness. i have since replaced that with out any difference being made. the block and head are the same as what i had before. i would love for someone to take a look at it and and pinpoint it rather than custom car care guessing which part i should replace till it resolves the issue.