I own a Mazda 626 Turbo 2.2L 1987 model GC.While decelerating from 2nd 3rd 4th and 5th gear my car appears to surge. I have a stinger 4434 computer and a multipoint ingection system. It has been professionally tuned but we recently adjusted the excellerator pedal so I'm not sure if that has affected the tuning at all.

Any suggestions would help.