Quote Originally Posted by scttydb411
check your motor mounts too. is it a thump you feel or only hear? is the thump more of a misfire/backfire?

when you let off the gas cruising your injectors are supposed to shut off and will take you totally lean, but if there is an injector leaking or if the car doesn't go into the fuel overrun cutoff or if the car doesn't go to 22in/hg or higher of vacuum (sending it into fuel overrun cutoff) it will still be giving it fuel which could be lean or overly rich depending on how much. this could be causing misfire situations too.
Its a thump that I actually feel. The car jerks in a way. Thanks for the help I'll give it a look. If anyone is local (or I can meet up) and want to give it a look see, i Would really appreciate it. stay in gwinnett