I have a 1990 Mustang lx that started off as a 2.3 AOD car that in the last 2 years I have swapped a brand new 5.0, T5 and all the GT parts to go along from a 1993 GT. Since I have finished the swap, it's been nothing but problems, firstly I accidentally wired the plugs in order for a carbureted engine and had a horrible misfire but noticed that only the #3 and 4 cylinders were not firing by feeling the exhaust headers. once I noticed the issue I reorganized the plug order to standard H.O firing order and once I did that it fired right up and idles on its own but I'm still noticing its headers are cold now on 2 cylinders on each side, I think cylinders 2,4,5 and maybe 7. it doesn't die off on its own since the timing is slightly advanced for a higher idle but I've put the cats on with the rest of the exhaust cut off just behind the transmission and even with those on I hear a ton of piston noise and the misfire is quite noticeable, I have videos that I will add onto this thread but I can't figure out why it would be misfiring in such a strange order, I have yet to dial in my fuel pressure so I have hopes that that's it but I can't see something that small causing that big of an issue, any experts please listen to the videos and tell me your thoughts. it sounds very rough in the first video because it was open headers at the time, but I just want to put my concerns behind me and be done with it. Any other ideas would be greatly appreciated, for reference, this is a 1993 convertible engine harness and ecu paired with a 1990 lx body harness. the wiring connected perfectly my only concern being the 2 fuel pump relays and the slightly different relay behind the ac unit in the dash, but the car still primes and runs, the engine and rotating assembly are brand new with rebuilt gt40p heads and a brand new t5 along with new mcleod clutch and flywheel. flywheel and balancer pully are both 50oz counter balanced. new fuel pump, injectors cleaned up fuel rail and lines. every part on this car has either been newly purchased or cleaned/rebuilt. Thanks again