razgris1

Ok so I bought a 2006 F150 with the 5.4 3 valve and I have questions. I didnt notice any issues on the test drive, but I didnt lean into it hard either. Shortly after getting the truck I was curious about the power so I put the pedal to the floor and the truck wouldnt stop falling on its face like it had several misfires or timing was way off. Engine light came on but after I had let off and let it compose itself the light went away I do hear the ticking from the engine and I have to keep the pedal in a certain range so it doesnt shutter. If im on the freeway and have to accelerate I will normally turn the overdrive off so it will downshift and not stutter. Its like if the load on the engine is light and I slowly accelerate it will start shuttering until I press it far enough to downshift. I tried unplugging the VVT valve and drove it around a parking lot and it did the same thing. Any ideas before I go into the engine and start replacing parts? It runs fine at idle, may feel a slight shutter every blue moon. From a stop I cant go too far down on the gas without it stuttering.

SilverSport

more knowledgable than me will chime in soon I'm sure but have you checked the simple things???...air filter and make sure the foam seal is good or replaced, clean the throttle body, clean the MAF, make sure the FPDM (Fuel Pump Driver Module) is good and not corroded, gas filter been replaced at some time, how long has it been sitting???...good gasoline???...

Good Luck with your truck,

Bill

Falbeon

How many miles? Could be time for new plugs and boots and springs for the COPs in addition to what SilverSport said

SCORGE

Need miles and some previous maintenance info

BadFish523

Sounds more like a misfire that the phasers to me. Probably needs the usual new plugs, boots/springs.

F150Torqued

^^^^^ I vote for @BadFish523

You describe the TYPICAL misfire symptoms for this generation engine. Get your Lisle Tool. It's time for a plug job.

Do a good, complete, careful plug job. By 'complete' I include new Boots & springs - an replacements for ANY broken COP clips. The boots may look OK but they dry out with age and many heat cycles, then loose their ability to insulate against the very high spark voltage. 'Complete' does not include COPs. They seldom fail, but often get corrosion on the tip to spring connection. Clean it! By 'careful' I mean hospital clean. NO greasy finger print on ceramic. Handle plugs 'carefully' - discard and don't use a dropped plug. Torque new ones properly - WITH torque wrench (25-28 ft.lbs, no more/no less). Use a small amount of dielectric grease inside plug end of Boots to help them slip onto plug and seal moisture out. Clean COP connectors (both Male/Female) with a good contact cleaner and make 'double dog' sure they SNAP properly - and make a good connection.

You might pick up some other good information from my experience with identical symptoms posted here: https://www.f150forum.com/f4/5-4l-3v...6/#post3930018

DarrinT04

same here. if we knew the mileage and maintenance info like scorge said we would have a better idea of problem

razgris1

It has at the moment 190,000 miles. As far as previous maintenance goes I don't know other than the first oil change I did on it about 1000 miles ago. This is a first I've heard about a misfire issue with these engines, all I've really heard are they are good engines but the phasers are their Achilles heel.

SCORGE

I'd vote misfire(s). Go ahead and plan to do plugs and boots/springs, It's about 100 dollars in parts a couple hours of your time. At 190k, I'd like to think they've been done before.

dukedkt442

Plugs/boots, that's classic misfire range. Use the upgraded SP546s. These engines have phaser/timing issues, but those would be accompanied by very audible warning signs. They are very sensitive to misfires if not tuned up properly and cleanly. Hopefully they're not original plugs, in which case the gaps would be large enough to have burnt out the coils, not to mention extraction consuming a weekend of your time.