My 2006 5.4 has a skip or miss or something! This only happens when increasing speed from about 45 to 50, gradually. If I accelerate rather hard it doesn't do it. Feels like loosing a cylinder (plug/wire). Sometimes it will do it 3 or 4 times in a row, and once past 50 it is fine. Seems to do it more often with 87 Octane and less with higher Octane but that may be a coincidence or my imagination. Truck has 123,000 miles on it.

 

Is it turning on your CEL or throwing a code?

 

When was the last tune up done?

 

Replace all your sparkplugs and COPs

 

Thanks to all threads......AK_Cowboy, Connor FX4, Ricks 06.....sorry but what are CEL's and COP's? No codes, plugs are 3rd set in 123K. Thanks again.

 

Looked up COP and CEL. No codes. Have had coil and plug failures in the past and they are always there...haven't had anything that only occurs at one speed and only when accelerating gradually. All plugs and coils = $1000.! Any other ideas? Thanks much!

 

Take it to a shop that has a real tech 2 scan tool. It's gonna be a coil or a plug and it does store the code just doesn't display it because it has to happen more than once in so many drive cycles. Shop is gonna charge you but when they tell you which one it is then clear the code, and change the coil pack to a different cylinder. Drive it, take it back and see if the problem followed the coil. If so, that coil pack is bad. If it doesn't then it's the plug. But if it is the coil I would still change the plugs because the bad plug is probably what ruined your coil pack. Good luck.

 

Change your fuel filter, and clean your MAF and throttle body.