Ford V10 shutter/ misfire only in overdrive diagnosed/ fixed
Thought I would share my experience with this and what I found incase other folks have a similar issue and want a possible resolution. Several weeks ago truck started what I would describe as a shutter or misfire. Its the excursion in my sig picture. Truck has around 100K. Plugs and boots replaced 4K ago by me. The symptom would only appear when in OD between 40-50 mph and 12-1600 rpm when going up a slight incline with light acceleration. If I pressed more on the gas forcing a downshift problem went away. Problem not exhibited any other time.
No CEL light on and when hooked to scanner no codes were current or none pending. Decided to chase a possible cylinder misfire. I didnt think it was tranny related as the rpms didnt fluctuate when truck was symptomatic. Also didnt think it was the torque converter ( was hoping it wasnt).
Hate just throwing parts at a problem so I had to isolate cylinders to figure which if any were misfiring as I was not going to buy 10 coils ($400) and hope for the best. On my scanner went into mode 6 diagnostic monitor tests. In there I used test $53. It gave me a list of all 10 cylinders and any misfires sensed. Sure enough they all had 0 except #2 and #7. #2 had over 800 and #7 had 1020.
Replaced coils/ boots/ plugs in those two cylinders with new Motorcraft units.Pulled plugs looked great, what gives I thought. Been driving it and problem appears fixed.
So why no CEL light or code? Why did electrodes on pulled misfire plugs look ideal? Well I did some digging around on the net and apparently when in OD the air/fuel mix is leaned which requires more voltage to ignite. Marginal failing coil cant supply enough and a miss occurs. Miss only occurs then and not during other driving conditions so the percentage of misses never gets to the threshold to throw a hard fault/ code. Other folks on here with more knowledge can probably explain this better then me.
Hope this helps someone. Total repair cost me under $100 could have been much worse.
No CEL light on and when hooked to scanner no codes were current or none pending. Decided to chase a possible cylinder misfire. I didnt think it was tranny related as the rpms didnt fluctuate when truck was symptomatic. Also didnt think it was the torque converter ( was hoping it wasnt).
Hate just throwing parts at a problem so I had to isolate cylinders to figure which if any were misfiring as I was not going to buy 10 coils ($400) and hope for the best. On my scanner went into mode 6 diagnostic monitor tests. In there I used test $53. It gave me a list of all 10 cylinders and any misfires sensed. Sure enough they all had 0 except #2 and #7. #2 had over 800 and #7 had 1020.
Replaced coils/ boots/ plugs in those two cylinders with new Motorcraft units.Pulled plugs looked great, what gives I thought. Been driving it and problem appears fixed.
So why no CEL light or code? Why did electrodes on pulled misfire plugs look ideal? Well I did some digging around on the net and apparently when in OD the air/fuel mix is leaned which requires more voltage to ignite. Marginal failing coil cant supply enough and a miss occurs. Miss only occurs then and not during other driving conditions so the percentage of misses never gets to the threshold to throw a hard fault/ code. Other folks on here with more knowledge can probably explain this better then me.
Hope this helps someone. Total repair cost me under $100 could have been much worse.
