02 3.8 mustang, has an intermittent miss ( but not steady) under mid to hard accel. Did a complete tune with plugs wires, all filters and problem returned after a short time driving. I then found a bad wire and replaced all wires with another new set, still same problem. I had a check engine light come on some miles later with a PO402, high EGR flow code. I replaced the presure sensor and reset the check engine light with no other codes found. The car appeared to run normal for approximately the first 20 to 25 miles then the same problem returned. It doesnt do it 100% of the time but it is mostly always present.

 

Did you ever get an anwser? My Mustang is doing the same thing and I haven't figured it out yet.

 

Sounds like a coil pack dying

 

Since posting I had a check engine light come on. I had A P1518 code which is an intake manifold runner control stuck open. All the issues I'm havin are the same symptoms of a bad controller. for smoother Idol and low-spee for smoother Idol and low-speed driving. And it opens the runners above 3000 rpm for more performance and power on top e thisken and hope it fixes my problem. but I'm hopin the 40 400 Karsten parts will fix both my

 

Having issues with my phone and post not correct. $400 experiment to see if it fixes my runablity problem.