HI ALL MY TRUCK HAS A SLIGHT MISS THEN THE CHECK ENGINE LIGHT CAME ON SO IT TOOK IT TO AUTOZONE AND IT SAID MISFIRE CYLINDER 4 WHAT CAN THAT BE I WAS WONDERING
IF A LEAK AT THE EXHAUST BY THE SENSOR WOULD THAT BE
THE PROBLEM THANKS

 

all caps means you are yelling.

the most common problem for the #4 coil is there is a hose just above it that leaks coolant on the coil and shorts it out. look just above the coil and you will see a rubber hose attached to an aluminum one. if it doesn't have a screw type clamp on it put one on it! if it does have one make sure it is tight. some people even loosen the clamp and push the rubber hose further up the aluminum one then tighten the clamp.

 

What year F150? does it have individual coils or a coil pack? Cylinder misfire can be caused by ignition system, coil pack, or injectors. Pull the plug and replace it even if it looks good.

good luck

 

The info you gave indicates a mis firing cylinder on number 4. What about that is hard to understand?

 

I had my ses light appear, and went to autozone to get them to read the code(misfire #4). I bought a $41.99 coil and replaced it within 15 minutes of starting using a 7mm deep socket wrench. You may want to consider changing your plugs if you haven't already. This is all assuming you have a 5.4

 

most of the threads here that started with a miss fireing #4, was soon followed by low fuel rail pressure bank 1 or / and 2. so i would look into the emission system as well. if your puter is leaning out the fuel because of clogged / restricted vaccum or egr lines. but not long enough (yet) to indicate. than changeing the plugs wont help for long. i would suggest you search the site for the sea foam / deep creep procedure and the threads concerning cleaning the throttle body and the egr system.

this seams to be common on both the 4.6L and the 5.4L. so i would start by cleaning those systems first. that way you know there not the cause.