So I'm stumped here.

Apparently yesterday (no known reason) my sons truck started to develop a miss (so it feels like to me).

2005 f150 5.4 auto 215000km 4x4 stx
No specific cylinder codes. All general codes.

P1000
P1464
P1550
P1703
P1780

None of which I can see causing the miss. No check engine lite, no other codes. Not sure what to look at next.

Any suggestions. I am starting to disconnect the coil packs one at a time and see if I can pin down the cylinder.

 

I'll add that he has cut his exaust off and strait piped it but cats are still on. Just no mufflers

 

P1464, you prolly left the AC on when you ran the KOER test.
P1550, you prolly didn't cycle the steering wheel when you ran the KOER test.
P1703, did you cycle the BOO switch when you ran the KOER test?
P1780, did you cycle the transmission OD switch when you ran the KOER test?

 

Ac was probably on yes, I left the steering wheel as it was, no to brake switch and didn't cycle transmission

 

Then ALL of those codes are irrelevant due to testing error.

To troubleshoot mild, non-MIL misfires, use your scan tool to go into the Mode $06 data and look at the individual cylinder misfire counts. See the relevant OBDII manual (download for free from www.motorcraftservice.com) for your specific model year for the PIDs and TIDs. Note that the misfire count data is often on a per-drive basis and resets when the power is cycled, so you'll need to read the counts during the same power-on cycle that you experienced them.

Mild misfires like these are common and are usually caused by a worn out spark plug, boot, spring, or a COP that's starting to break down internally.