I have a F150 Lariot With the 5.4 Triton. It only has 80,000 miles on it and has a strange misfire sometimes. Sometimes when going down the HWY and you go to pass or floor the accelerator, it will go to missing and popping, and sometimes it will take right off like it is suppose to. I have no idea what might be causing this. It runs excelent most of the time until you floor it. the check engine light started flashing the last time it done this and now is staying lit up. Any help on this problem would be great. Thanks.

 

Replace the spark plugs ASAP or you will be replacing the cat converters as well.

 

I know on my Lightning, a bad COP will make this happen, supposedly they are really only good for 50k miles. As mentioned above I would change the plugs and check the COP's.

 

What about the coils too or just the plugs? What plug should i go back with. I have heard bad things about the two piece factory plugs and have also heard bad thing about the champion one piece replacement plugs. Has motorcraft corrected the issues with thier plugs?

 

I use NGK...Coil packs are pricey if you could find the one misfiring then you could do one...

 

just wondering what kind of plugs to go back with

 

NGK..................

 

Thanks for the help! I will try this and post back later Thanks!!!

 

I would stick with Motorcraft SP515. Put antisieze on the ground shield and they will come out pretty easy the next time u have to change them.