been having a issue with 5.3 swap in my 84 C10 backfire on acceleration running like crap replaced all kind of parts and then I rechecked my injector wiring and on bank 1 I had the wiring hooked up to wrong injectors I was going by length of redone stand alone harness and not by actually firing order, weird thing is it wasn't setting any misfire codes but apparently the cylinders were filling with fuel not burning at the right time, rookie mistake so injectors and coils are meant to work together so if you pulled your hair out like I did for months replaced all kinds of parts checked compression pushrod length new plugs new wires tuned 25 times and still misfires maybe take a look at the wiring as of today I finally got to hit the gas pedal and smoke the tires and go sideways great day little more tuning for sticking high idle and ill be set for now