Mxvosen134

Hey guys i have a 2011 f150 that has had 2 misfires i replaced the 2 plugs that were cracked and the truck ran amazing like new again. They were both at different times and different mileage. A few weeks ago the truck started missing again took it down to ford and they diagnosed it saying it needed all plugs replaced. truck ran great for about a week but is running horriable again. The truck tends to back fire a lot especially at half throttle acting as if its cutting out...... At full throttle the truck will reach a certain point and loose all its power and start shuddering. Had the intercooler off last night dried it out put it back on also changed my oil while i was at it trucks still running like garbage it will not throw a check engine light. The past few misfires before this it did and went into limp mode.......... Now it wont i cant figure this out for the life of have been trying though. Unplugged the air flow sensor on intake tonight loss of power but no missing or back firing while unplugged. Was thinking maybe its the tube coming from intercooler to the intake that has some water in it but i really dont know. Its the 3.5l v6 ecoboost. Truck currently has 46,345 miles on it to date. If anyone can help that would be aweome ! no pending codes no light

brucesears

It sounds like you have a cracked plug or plugs. Miniscule cracks get worse with time and carbon track. I would pull them and inspect very closely for crack and narrow the gap down to .028. If it still persists you may have a bad coil.

maplelakeduckslayer

Plugs...they are super easy to do yourself. I have done mine 4-5 times in 96,000 miles...these trucks like to chew through them. If my truck every doesn't feel right first thing I check is plugs is the most cost effective thing to look at, and is the culprit more times than not.

vozaday

Hopefully like said above it is plugs. But it is weird it only lasts a week or so per set of plugs. Have you had the startup noise? Other than that maybe have a look at the intake valves and see if there is any build up. These are more extreme diagnosis but a couple ideas.

Kenferg1

Replace the boots on the coils as well.

Tothemax

Have you had it in for the most recent TSB?