I have a 15 f150 lariat with a 5.0 coyote bought it used at dealership with 125k. 4mo later misfires on cylinders 3.5 and 8 .I replaced COP's and plug on all cylinders. Misfire returned took to shop cylinder 8 was dead at 22lbs fuel pressure 3 and 5 were at 92lbs pressure was bleeding past the rings according to shop. So they quoted me 15k for engine swap. I bought reman/ rebuilt from fraser who out sourced it to Summit Racing who intern got it from Apple Ford.with 5 yr unlimited no fault warranty had local shop install saved maybe 3k from original quote. within 1month after new installation the misfires on 3 and 5 returned. 2weeks ago I had new COP wire on 3 and 5 installed as wel las new injectors. Yesterday cylinder 3 and 5 threw PO300 PO303 and PO305. Im at a loss as to what direction should i be trouble shooting / repairing. so Im seeking the following advise and direction.
1 which forum should this issue be sent to to address these issues?
2. Is there a way that Ican troubleshoot the PCM?ECM my self to determine if the issue is stemming from it as opposed to mechanical issue?