7/07 f150 Lariat, 4x, 5.4 3v. Don’t laugh …
322.000 miles. Ran fantastic up until it didn’t .

First it was #4 coil. Fixed. Literally next day, #8 coil. This Time I decided to change all motrcrft
coils and plugs as well. I think plugs may have 150.000 on them.

Changed out all plugs except #6. That one I rounded off with an impact. Thought it was my 8 point socket turned out it was a worn out 12 point.
. #8 plug was finger tight and bridge had melted off .To get to #4 spark plug I carefully removed the PCM.

Put everything back together , started the truck and now I have a bad miss. Not a compete cylinder miss but bad enough. Ofcourse I went back and double checked my work and everything was fine.

I scanned it and it was PO335 and PO115E

What I have done:
0. new Maff sensor.
1. Changed out all coils and plugs with Mtrcrft.
2. New fuel injectors Bank#2
3. Compression check all cylinders.

Bank# 1 :
1 117
2 90
3 151
4 n/a hard to reach

Bank # 2
5 150
6 N/a rounded off plug
7 151
8 132

I know 90 lbs is real low but she’s got high mileage
She only has to give me another 5 to 7 thousand miles and then I’ll replace the motor.
I don’t think it’s compression because when I turn the starter over it all sounds even. Maybe that’s wrong.

I did a timing, phasers etc job about 150.000 ago.
im planning to do a throttle body cleaning.

Tonight I was checking it out again and happened to scan again.
Tonight’s scan was codes in every cylinder.
it’s sounding more and more like an Ecu. I live on bumpy dusty dirty roads so maybe something’s come loose. Im going to send it in for repair and if that doesn’t do it I guess it’s going to Ford tech.

Any insight would be much appreciated. Thank you.6

 

It seems you have a problem with crank sensor circuit . Its down by ac compressor and road dirt . I would clean the connector real good , also the cable wiring to it is known to fail as it is down low on engine near road and salt . Wiring is a shielded cable ground on shield . Some guys have opened that cable to find white crusty stuff inside .
Sometimes the sensor goes bad ,other times the reluctor wheel teeth get damages from broken plastic guides ,it can also get keyway damage since it is aluminum .
I would clean it maybe put a new sensor in , inspect wire harness to it . Is your tach jumping around ? Even if you get a reman you will have to fix that wiring first .
it is shielded to keep stray signals from getting in there to confuse PCM .
One thing you could do is drop oil pan and look for broken guides ,that will tell you if you need to open timing cover . Hope you get another 100k out of this engine .
Looks like you need to deep clean throttle body .

 

Thank you for the suggestions I’ll try that .