A friend of mine has an 03 F150 5.4 with about 240k that I work on occasionally. Last winter he had 3 coil packs go bad so I replaced those, along with a full set of Motorcraft plugs. Ran just fine afterwards. So this winter he has had more coil pack problems so last weekend I replaced the other five. It threw codes Monday night and he took it to the auto parts store to run them. Came back saying number 3 plug and upstream O2 sensor driver side. (I wasn't given the exact codes) He only has these problems in winter though. I hate to go and replace an o2 sensor or anything else if it could just be nasty Indiana winter blend gas. I'd love to hear anyone's thoughts on where I should go from here. Thanks in advance!

Eric

 

wow where does he drive? My f-150 has the same amount of miles and I bought it with 243,600 on it and I'm in Indiana too it's a 03 also

 

He's in Southport, I'm in Speedway.

 

im in mooresville my king ranch was up north in the Rich part of Indy haha

 

It could be a lot of things including the Ox sensors but more likely something else. I would start with easy and low cost maintenance if this has not been done for a while. Specifically

Replace PCV valve (less than $10)
replace fuel filter
run a can of injector cleaner through the next tank of gas
Clean the MAF valve (maf cleaner about $9.00 at autozone)
change air filter.

Less likely

Inspect vacuum lines and replace damaged lines. Make sure the vacuum line to the PCV is not damaged when you replace PCV valve

Good luck

 

Bump

 

5fours don't use coil packs, - never have. Sort of makes it difficult to help.

 

Try swapping #3 for #1, clear codes and see if it pops up again. Will determine if it's a coil or not.

 

COP, coil on plug, coil pack, whatever youd like to call it theres 8 of them, and its a 5.4.

 

It's not what I like, - it's what it is and what it ain't. Figured if you could learn that much, you might be able to fix it. It seams your having difficulty with the basics, - just trying to help.

Yea "coil packs" were used on the earlier 4.6Ls. Not on the 5.4L's. That's just how it is.

Hell, don't you want to know what your working on ? It's just a coil. COP = Coil Over Plug. Not a pack of them.