2007 F150, 118k miles, 5.4 FX4. Original engine/transmission.

Started to get some shuddering and P0358/P0308 (and other cylinders) codes so I changed the plugs. I did the front 6 (all broke) and I had a shop down the street do the back 2 (both broke). Replaced all plugs with Autolite Platinum HT15 plugs. Ran ok for about 150 miles, but then it started missing again, codes P0351/P0354/P0355/P0358, so I changed the COPs out with Denso COP on Cylinders 1/4/5/8 (front 2 and rear 2). I used plenty of dielectric grease on the boots. Now I still have a P0358/P0308 code showing. I just swapped the #8 fuel injector, no go. Still running like crap. I've checked all lines and connections and everything appears tight. Truck runs like complete crap. Is there anything else I should check? I'm going to go re-torque the plugs now, just running out of ideas. Compression test?

to make things worse, after the plug change and 150 miles of running fine, as soon as the codes popped up and truck started running bad my AC immediately stopped working. Coincidence? I know the systems are independent, but just seemed odd.

 

Ok. I had the same problem. The furthest back COP on the passenger side firewall. That is somehow tied in with the ac. Check your cop closely for cracks. Then check the connector and the wiring going to it. Somehow my cop wire got up againt the high side ac line and was shorting out. At the same time i had a hairline crack in the cop neck. Its weird but my ac shut off and was bucking like hell before i tracked down the problem.

 

thanks, I'll go check that. Hopefully this is it. Any other suggestions from the community?

 

that didn't work. I did the following:

1. I changed the #4 COP out, applied more dielectric grease, re-torqued plug.
2. I re-torqued all other plugs
3. checked all hoses/lines to make sure they were connected.

I'm at a loss here. Anyone else have an idea?

 

went to Autozone to use their scanner, thinking maybe my "inexpensive" scanner wasn't picking up some codes. Nope, same codes. Plan now is:
1. Check each COP connector with Ohmmeter, if that checks out then
2. empty wallet at dealership

 

UPDATE: to anyone that has had this issue, specifically a P035x error, don't replace anything right away, go to the dealership. There is a tech service bulletin out that details the issue, faulty PCM - see below. This is what was causing the misfires and A/C to shut off. $1,250 later I should have my truck in about 5 days as the PCM ships directly from Ford.


20680 GAS ENGINE COIL ON PLUG(COP) DIAGNOSTIC TESTING
WHEN DIAGNOSING COIL ON PLUG (COP) IGNITION PRIMARY CIRCUIT MALFUNCTION DTC'S P035X-P0360
ALWAYS VERIFY HARNESS INTEGRITY USING PCED PINPOINT TEST JF. IN RARE INSTANCES COIL DTCS CAN
BE A RESULT OF PCM DRIVER FAILURES. TO CONFIRM PCM DRIVER FUNCTION USE IDS TOOLBOX OSCILLOSCOPE
"ESCAPE PCM DRIVER" TEST TO VERIFY PCM FUNCTION. WITH NO VEHICLE SESSION ACTIVE SELECT TOOLBOX
THEN OSCILLOSCOPE FUNCTION. SELECT THE ESCAPE PCM DRIVER TEST. FOLLOW HOOKUP SCREENS FOR
CONNECTING THE CURRENT CLAMP AROUND THE HARNESS AT THE ENGINE POCKET CONNECTOR OF THE PCM.
MISSING COIL DRIVER PULSES FOR NON-STANDARD COP COILS CAN BE IDENTIFIED USING IDS POWER BALANCE.
IF MISSING PULSES ARE OBSERVED FOLLOW PCED DIAGNOSTICS TO RESOLVE. IF ALL COIL PULSES ARE PRESENT
DON'T REPLACE THE PCM. TEST DISPLAY SCREENS ARE AVAILABLE IN THE ESCAPE DRIVER TEST HELP LIBRARY

EFFECTIVE DATE: 02/25/2009
20677 GAS ENGINE MULTIPLE COIL PRIMARY CIRCUIT DIAGNOSTICS
DIAGNOSTIC TROUBLE CODES(DTC) P0350/P035X-P0360 CAN ONLY BE SET BY A PRIMARY CIRCUIT MALFUNCTION.
A SECONDARY IGNITION FAILURE(SECONDARY COIL WINDING OR SPARK PLUG)WILL NOT SET A P0350/P035X-P0360
DTC. IF A P0350/P035X-P0360 DTC HAS BEEN SET, THE PCM WILL INVOKE FMEM (FAILURE MODE EFFECTS
MANAGEMENT)WHICH WILL SHUT DOWN THE INJECTOR FOR THE FAULTED CYLINDER IN ORDER TO PROTECT THE
CATALYST. THIS IS NORMAL OPERATION. DO NOT CONDEMN THE INJECTOR WHEN A P0350/ P035X-P0360 DTC IS
PRESENT. A PRIMARY CIRCUIT MALFUNCTION WILL ALWAYS SET A P0350/P035X-P0360 DTC BEFORE A
P030X(CYLINDER X MISFIRE DETECTED). IF THE CAUSE OF THE PRIMARY CIRCUIT MALFUNCTION IS A SHORT TO
GROUND, THE IGNITION COIL WILL BE DAMAGED WITHIN SECONDS; HOWEVER, THE PCM WILL NOT BE DAMAGED.
DON'T REPLACE THE (PCM) WITHOUT VERIFYING COIL DRIVER FUNCTIONALITY.