Engine Popping/misfire

[Cory Berg]

So I've been chasing this problem for about two months now and I've been slowly replacing parts that needed to be replaced.

At a cruising speed, no matter the speed, if I roll onto the throttle there will be several loud pops that sound like misfire. After the pops, it sounds/feels like a switch and all the power picks up. Sometimes when I roll onto the throttle there are no pops but there is an obvious lack of power as the motor winds up.

So far I have replaced rotor, cap, wires, tps, iac, replaced with a known good coil.
She is an '87 running speed density, also.

 

[Mustang5L5]

Run the check engine codes.

87's do not have a check engine light, so no CEL will ever light up if codes are present.

Right off the top of my head, possible causes are faulty/dirty EGR, vacuum leaks, bad O2's or a bad BAP sensor.

If you run the codes (engine off and engine running) you'll get a better starting point