Random misfire

[DFRANCIS774]

I have an 06 5.4 that is have a constant random misfire. I have changed timing set, cam phasers, plugs, coils, fuel injectors, cam position sensors, or sensors, and catalytic converters. And still have the same problem. Some one please help before I drive this thing into a tree

 

[Bedrck47]

http://www.obd-codes.com/

 

[Habbibie]

Since u did all that and it still misfires it's down to two things, wiring to injectors or spark plugs is shorting or pcm took a dive.

 

[steelnewfie]

My 06 would not stop random misfiring after a plug (and all coil) change. Used all Motorcraft parts. To make a long story short these engines build up alot of carbon and often when swapping parts or applying dielectric grease we inadvertently cause some spark arking or shorting.

One bottle of Fuel System Treatment (Gumout with Regaine) improved my response, idle, eliminated misfires. I was chasing this thing for weeks and a bottle of carbon cleaner (get one with the special esters) fixed the works.

For fifteen bucks I recommend you throw a bottle in your tank prior to driving it into a tree. I was about to drive mine into the Harbor so I understand your frustration. Been ticking (literally) along now for over a month trouble free.

If no change I'd replace fuel and air filters, ensure your airbox is well sealed. Maybe FPMS the fuel pressure delivery module is known to rust out on the second gens.

Please update us when you find the fix!! Good luck.

 

[Lostneye]

Are there codes? If so what are they?

My 06 would not stop random misfiring after a plug (and all coil) change. Used all Motorcraft parts. To make a long story short these engines build up alot of carbon and often when swapping parts or applying dielectric grease we inadvertently cause some spark arking or shorting.

One bottle of Fuel System Treatment (Gumout with Regaine) improved my response, idle, eliminated misfires. I was chasing this thing for weeks and a bottle of carbon cleaner (get one with the special esters) fixed the works.

For fifteen bucks I recommend you throw a bottle in your tank prior to driving it into a tree. I was about to drive mine into the Harbor so I understand your frustration. Been ticking (literally) along now for over a month trouble free.

If no change I'd replace fuel and air filters, ensure your airbox is well sealed. Maybe FPMS the fuel pressure delivery module is known to rust out on the second gens.

Please update us when you find the fix!! Good luck.

I would try fuel system cleaner too. I'm partial to seafoam personally.

The FPDM is on the drivers side inner frame rail behind the rear wheel. The aluminum corrodes and lets moisture in. You can't tell as it's against the frame but I would definitely look into that. The new ones come with spacers to keep it off the frame. I had a random misfire that I couldn't find, not throwing codes and when I pulled the FPDM the aluminum was crumbling in my hand.

 

[Jb14]

Have you checked the Mass Air Flow sensor? or re-positioned MAF? Also check the wiring going to the MAF the wires have split and short out. If you have stock air cleaner box check to make sure you have no cracks and look inside the box, where the MAF is located inside if the scoop that is molded to the upper part of the box is damaged or chipped it will not have the proper airflow passing the meter and will throw it off. Lastly take off air box and see if rubber gasket attached to Throttle body is intact and seated properly.

P.S. Throttle bodies are known for issues as well

 

[DFRANCIS774]

still getting the misfire light. the only codes im getting now are p0345 and p0349. i have checked both cam sensors and wiring to the pcm reisistance at both wires is 0.00 I'm not sure what else to do at this point.

 

[DFRANCIS774]

Update some one please HELP I have an 06 5.4 that is have a constant random misfire. and no power on take off at. I press the gas and the truck falls in its face and nearly stalls. I have changed timing set, cam phasers, plugs, coils, fuel injectors, cam position sensors, O2 sensors, and catalytic converters, and VCT solenoids And still have also checked the continuity from the connector ends to the PCM connection. the same problem the only code I get are random misfire P0300, and Cam position sensor bank 2 P0345 and P0349 Some one please HELP