I have a 2011 F150 SC with the ecoboost. I keep getting Diagnostic code for cylinder misfire. Changed plugs and still does it under loads at time. moved coils around and will still throw a code on those cylinders. Any advise? Truck has 116,000 and has been doing off and on for thousands of miles.

 

What are the exact codes it is throwing?

 

Codes are P0300,P0305,P0301,P0306
Those are all misfire codes.

 

Which banks is it doing it on?

 

it's on cylinders 1,5,6

 

How bad is the misfire? Do you get a flashing CEL? 1,5,6 aren't on the same bank. The P0300 is a random misfire code for when the PCM can't determine which cylinder it is.

 

If you stay on ti long enough under a load it will hard set a code.

 

Is there water in your intercooler that could be getting picked up?

 

Thought about that also.

 

How old are your spark plugs? If you're getting P030x codes the coil is trying to do its job but something is making the cylinder not go bang. I would start with putting new Motorcraft plugs gapped to .030". That should go a long way to resolving misfires.

 

Done all that. Went to Colorado on a ski trip this week and it did it again so I replaced all plugs . Ran fine for awhile but now spits some under a load.

 

Curious on what oil you are running. My nephew went outside the stock parameters and had the same issues. Changed plugs, swapped coils etc. Was going to tear down the fuel rail, but did some additional searching. It seems if you aren't running synthetic and the right viscosity it can hamper the cam shaft revolutions and mess up firing etc.


I am no expert, just sharing what my nephew went through, He did an oil change and it helped, and after about a week everything was back to 100%.

 

Think I have it figured out. There is a TSB out saying to change the rubber boots on the coil. Been running fine since.