My 2001 F-250 with a 5.4 has a miss in it. It is the same whither it is hot or cold. It feels like it is electrical as it does not get any worse when it is under a load like a fuel problem, but I changed the fuel filter anyway. I also changed all eight plugs and ignition coils. This did not improve it any. The air filter looks good. If it matters the truck has 219,000 miles on it. Does anyone have any other ideas of what to try before I take it to a mechanic? Thanks for any help you can provide.

 

my f-150 did the same. plug in a code reader at an auto store to check codes. mine is a coolant temp sensor

 

Is it a constant miss that doesn't go away?
I'd run a compression test to see if it's a bad cylinder.

 

Yep, it is a constant miss, I'll have to look into that. Thanks.

 

You may have a short on one or more of your clips that plug the coils into the wiring harness.

I haven't seen it personally, but I have heard that you can run the motor at night, pull the light out of the hood, make sure it is DARK and look at the coils. If the clip has a short you may see a spark arcing from one of the connections.

Crazy sounding, but You may want to try it out.

Also, what kind of coils did you use?

Did you remove the boots to insure that the springs were correctly installed in the new coil from the factory?

When I replaced my coils, I removed the boots and found that about 3 out of my 10 new coils had springs just sitting inside the boots, not even installed properly inside the coil.

Just throwing ideas out that won't cost you any more $$

 

I used NAPA, but I did not take the boots off to make sure that they are connected, I will have to check into this this weekend.