I'm Having Some Issues With My Mustang, It Seems To Be Backfiring Through The Intake When I Shift And Let Off The Gas. Plus When I Get It To A Certain Throttle Spot It Jerks Back And Forth. I Don't Really Know What It Could Be Because I Just Got It Tuned And It Ran Fine, A Week Later It Started Doing This. The Only Thing That's Not New Are My 24# Injectors, Fuel Pump And Tps Sensor.. Everything Else Has Been Replaced. Could It Be One Of These? Your Help Is Appreciated.