Let me preface this by saying I give this post a 2% chance of finding a solution but maybe it'll be useful for people in the future.
So over the winter it seems my car has developed a propensity to throw misfire codes at high RPM part throttle. Particularly cylinders 3 and 5, and also random misfire (0316). This happens pretty much only when I downshift and cruise at high RPM (4500+) while I go through windy roads, under WOT it doesn't throw codes.
So the only recent thing that might cause this is over the winter I replaced some PS lines and I had to re-route my Alt cable, during routing I accidentally twisted the main power stud on the engine bay fuse box (common problem), it only twisted about 45 degrees so I moved it back and epoxied the plastic case back together. Might be possible that the bus bar maybe cracked and has a small area (and thus less current carrying capability)... Everything else seems to work fine though.
Towards the end of last summer I also replaced my crank position sensor from a different issue, I used a genuine motorcraft CPS tho... and as far as I know there's no crank sensor learn on these vehicles... I also did a comp test and everything was good at the time, I have no reason to suspect mechanical problems, the car cranks normal, has normal power, and normal idle vacuum.
What I've done so far:
Checked all plugs and re-gapped, been .022 up to .025 no difference. Swapped plugs 3 and 5 with adjacent cylinders, swapped in my genuine ford coils on those cylinders too with no avail.
Next step is to put all the original coils back in, maybe measure voltage at the coils. After that maybe swap old CPS back in, and inspect fuse box...
So over the winter it seems my car has developed a propensity to throw misfire codes at high RPM part throttle. Particularly cylinders 3 and 5, and also random misfire (0316). This happens pretty much only when I downshift and cruise at high RPM (4500+) while I go through windy roads, under WOT it doesn't throw codes.
So the only recent thing that might cause this is over the winter I replaced some PS lines and I had to re-route my Alt cable, during routing I accidentally twisted the main power stud on the engine bay fuse box (common problem), it only twisted about 45 degrees so I moved it back and epoxied the plastic case back together. Might be possible that the bus bar maybe cracked and has a small area (and thus less current carrying capability)... Everything else seems to work fine though.
Towards the end of last summer I also replaced my crank position sensor from a different issue, I used a genuine motorcraft CPS tho... and as far as I know there's no crank sensor learn on these vehicles... I also did a comp test and everything was good at the time, I have no reason to suspect mechanical problems, the car cranks normal, has normal power, and normal idle vacuum.
What I've done so far:
Checked all plugs and re-gapped, been .022 up to .025 no difference. Swapped plugs 3 and 5 with adjacent cylinders, swapped in my genuine ford coils on those cylinders too with no avail.
Next step is to put all the original coils back in, maybe measure voltage at the coils. After that maybe swap old CPS back in, and inspect fuse box...
