Nex
RIP CoronaRaptor
Have you looked at the IAC?
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I looked at the throttle body and cleaned it. Throttle % in Forscan looks stable as well. Figures.Have you looked at the IAC?
I haven’t, but I will. I’m starting to think it’s exhaust related, also because that’s basically all that’s left aside from the ECU. It is hard to believe an exhaust issue would only affect one cylinder… but maybe the misfires I’m seeing are a red herring to the idle problem anyway. Could maybe be a slightly weaker valve spring on that cylinder or something so it’s the one showing misfires, I have no idea. It’s odd it doesn’t produce misfires at a high rate, even when replicating the shudder. 5-10 per minute is still well within normal spec.Have you checked for a cracked exhaust manifold or broken stud? My truck did weird stuff like that when I had a crack between the Number 6 and 7 cylinders.
It sounds like you have replaced most/all components that could cause this problem. That said, I would do the complete idle relearn process to see if it corrects the problem. The relearn process takes 15-30 minutes and should not be rushed. This is how I do this procedure, turn off all accessories such as headlights, HAVAC and radio. Then disconnect the negative battery cable for at least 1 hour but over night is better. Reconnect the negative battery cable and start the truck without touching the throttle, let idle for 5-10 minutes then foot on brake put in gear(R) and hold for a minute then release brake and move a few feet brake shift to N wait a few seconds and shift to D release brake and move a few feet and brake again and shift into P. Repeat a few times then turn on accessories and make sure the AC is on max and repeat a few more times. Go for a short test drive and you're done.I haven’t, but I will. I’m starting to think it’s exhaust related, also because that’s basically all that’s left aside from the ECU. It is hard to believe an exhaust issue would only affect one cylinder… but maybe the misfires I’m seeing are a red herring to the idle problem anyway. Could maybe be a slightly weaker valve spring on that cylinder or something so it’s the one showing misfires, I have no idea. It’s odd it doesn’t produce misfires at a high rate, even when replicating the shudder. 5-10 per minute is still well within normal spec.
I’m out of ideas though. I’m gonna try to get the 02 sensors off and replace them as well as bore scope the catalytic converters.
I want to add some more things for you to check.
Check for corrosion of the pins in the connections for the Throttle body and......
Most importantly check the three PCM connections and I mean both sides of the plugs.
While the pins may look good, you need to open the back of the plugs and check the wires going into the pins.
Somebody on here had this problem and did a little write up on how to open check in there.
Ford does a real crappy job of taping up the loom to the plugs!!!
I would also check the starter terminal cables. there could be corrosion between the cable eye ends.