I have been over the vaccum lines replaced a number of them due to deteration and cleaned the idle control vavle, the car acts like a secondary ign miss but not that drastic it has been scoped a coulple of times with good results and it does it on a constant basis very light but noticable. I have even done a leak down test on all the cylinders hot and cold but holds good pressure on all cylinders and I can't see anything out of the ordinary, did not know if vavles have up or possible injector problems