Good day to everyone! I have a 2001 F250 superduty 4x4 with a 5.4 in it. the truck has been running great for the past few years with no major issues. I always use oem parts from oil & filters to king pins etc. A few weeks ago i was driving along and it started running on 7 instead of 8. Pulled the plugs and all 8 seemed to be burning fine(lite tan in color on plugs). I replaced them anyway and there's no check engine light coming on. On idle it seems to run smooth but if you get on the highway and leave it in overdrive you can def. feel it. I have to leave it out of OD just to go down the highway. It seems that first thing in the morning it's fine for about the first 5 to 10 minutes of driving then it starts to miss. Any thoughts on what it could be? I have about 104,000 miles on it.

 

Moved from general chapter discussion.

 

I have had the same thing happen twice with my 99 expedition 5.4. Both times it was a faulty COP. First time it was the number 4 COP at 140K, the second time it was the number 1 COP at 152K. I would let my truck run in OD until it threw a code (Check Engine light). After it throws a code, read the code if you have a code reader, if you don't have a code reader take it to a store in your area who will read the code for free. I believe AUTOZONE stores will read codes for free. (Once it throws the code disable OD so that you don't dump raw fuel into you catalytic converters.) Once you have the code you can look up the cause/s and make a better decision or troubleshoot further.

 

Thanks for the info. I'll try your suggestion and see what comes up. Yeah i have my own code reader, would'nt be caught without one! Electronics are fine as long as you dont have a problem then....I like the old back in the day carb and distributor! Alot easier to troubleshoot! I guess they both have there pros and cons...once again and i will keep the forum updated on my finds...

 

coils on plugs seem to be notorious on the later mods for going away , or maybe a bad injector ????

 

Your welcome. I forgot to mention the codes which I read when I had my problems with the COP's. I read P0304 when the number 4 coil was the problem, and P0301 when the number 1 coil was the problem. Good Luck.

 

https://www.ford-trucks.com/forums/1...elerating.html
Hope this helps...

 

I agree with what has been said that you probably have a COP problem. A Ford tech friend of my told me that when you change plugs on some models that the boots should be changed also. He said that he has changed plugs and everything was OK for a couple of weeks and then a miss would show up due to spark jumping to head through the boots. So if you haven't changed them it might save you a little heart ache if you changed the boot with the coil.