2001 F150 5.4L/4R70W showing 85,000 miles, Misfire on #2 & #5 cylinders along with several trans position switch DTC's & O2 sensor circuit DTC's.
The Trans Position & O2 DTC's were caused by the trans harness being against the right exhaust manifold...Common issue on all 10th gen & newer F150's/F-Series SUV's once "hands" have been on it.
#2 misfire was from a broken coil control circuit from being pierced during some barbaric testing.
#5 misfire ended up being a broken exhaust valve spring, Initial testing yielded good leakdown & static compression numbers....Also verified spark & fuel delivery along with no vacuum leaks.
A dynamic compression test yielded @ 30 psi while #2 had 80 psi at idle, Revving the engine off idle would correct the #5 misfire once the excess fuel burned off the plug & the off idle dynamic test confirmed that.
I've seen many 3V Modular Fords break valve springs along with the early 6.2L's....Think this is the first 2V Mod I've ran across.