Hi guys, i am new to this forum but have read countless threads trying to diagnose what problems i am having any help will be appreciated.
Here is a little about the truck. It is a 2013 F150 3.5 ecoboost. SCT tuner w/ 5 Star custom tunes, Strait pipe from cat's back.
A few days ago i was pulling an empty horse trailer and when i came to a stop/slight roll i felt the truck jolting. Shortly after the check engine light started flashing and then stayed on solid p0304 code showed (cylinder 4 misfire). I flashed to truck back to stock and drove it home. (note the truck was on 91 octane performance when pulling the trailer) The truck ran fine and only acted like there was a miss when at a stop and would jolt. The next day i put all new plugs in the truck (sp534's gaped at .030), the cylinder 4 plug did have a crack in the porcelain. When i put everything back together the misfire was worse and now misses all the time not just at an idle. I swapped coils to see if the misfire would follow and it did not follow i even replaced the plug with another new plug to see if i possible cracked the plug while putting it in. The only other thing i can think is wrong is that the injector is stuck open. (Yes the plug does look wet when taking it out as it will if the cylinder is not firing?) or worse case the ECM. any and all information would be appreciated the truck currently has 63,000 miles.

 

Swap injectors and see what happens. If #4 is still missing, do a compression test.

I think you may have made a mistake by using a performance tune for towing, that's what towing tunes are for.

 

5* has a 91 performance and tow tune. He might have been on the right one.

Get a test noid and see if you're getting spark signal to the coil.

 

Cleaned and swapped injectors and still have misfire p0304 I will do a compression test tomorrow and see what happens.

 

It sounds like you're not getting a signal to the coil if the plug is wet. Test for signal to the coil and go from there. A compression test won't hurt but might not be necessary.