Well brand new plugs in the truck and when the truck is cold it still misfires. Engine light flashes but went off. So I had the engine code read it said "Cylinder 1 misfire", the engine light came on and stayed on after leaving there. So I went back later in the day to Advanced Auto, and had a guy I know up there read it again. This time "Cylinder 6 misfire". Yet the whole day I never had not one issue out of the truck. It didn't seem to misfire at all. So I had the code cleared, and drove it for awhile. Well later on that night I was riding around with my girl, and driving it a little rough. I had wounded it up a few times on the road. The engine light has once again presented itself. Yet I cannot feel it misfiring at all. In fact there is no hesitation at all. Any suggestions? COP's maybe? Sensors? I have heard that changing the plugs often can show the COP's are bad as well.

Is there anything else? I am getting ready to take my TB apart, and give it a good cleaning. Clean the MAF, and TPS. I doubt that, its whats causing my issue. Like I said the truck only acted up noticeably when it was cold out, once it warmed up I couldn't feel no misfire at all, and even when it was misfiring it wasn't nothing like before. It didn't pop or sputter, or none of that stuff. It was just real rough running. It actually quit after I let off the gas, (the truck had begun to warm up).

 

im leaning towards a bad COP.

 

When's the last time you changed your fuel filter? Should be done every 25k. Your engine can't fire right being starved of fuel. Just an idea..try it and see.

 

Fuel filter changed recently... not even 3000 miles ago.

 

i would still lean towards the COP being bad. sure sounds like it to me.

 

Yeah with the plugs never being replaced and are now new its got to be the COP's.

 

Replacing them then next... I found some on ebay can anyone say whether or not they'd work? NEW IGNITION COIL 2004-2007 FORD F150 5.4L DG511 (8) - eBay (item 110486527793 end time Jan-17-11 08:08:47 PST)

 

what plugs did you use? i have heard of people having problem when replacing the plugs with non motorcraft plugs. sounds stupid, but no stupider then changing everything else on the truck to find out it was the plugs all along.

 

That happened to me a few years back on my 4.0 l SOHC Explorer. Changed out the stock plugs for Bosch Iridiums. Apparently the tolerances were close but not close enough. I had a lot of rough idle/ misfire issues. Went back to the dealership and was told the plugs were"off" just enough to create the problems. Replaced with Ford plugs and the problem went away.

 

So true!

 

There is a motorcrafts in it.. trust me

 

Bosch plugs cause random misfires in just about all OBDII Fords. Dont use them. I know you are running Motorcraft. Just stating this for the guy that posted about the SOHC Explorer. Run the plugs that are designed for the engine unless you have power adders. Otherwise it is not necessary and will cause issue. Not to mention they usually cost more. You def have a COP issue. Once the COP's are disturbed from removal and reinstall for the plug change the issues arise. It is very common. And for the ones listed above for 114.00 for a set of 8 off of Ebay. They are aftermarket. They will likely be fine for a little while, but then you have misfires and be replace COP's for the rest of your ownership of the poor truck. That lifetime warranty on those cheap parts means just this....you will spend the rest of your lifetime replacing them. Spend the 40.00 a piece on the Motorcraft ones and forget about them....

 

These say they are motorcraft... but even if they aren't at 114 bucks for 8 of them thats cheap. Not gonna pass up on that though.. Money is tight at the moment, winter time means the business is slow. So not a lot of work.

 

Did you change the boots on COPs when you changed the plugs? That can cause a misfire as well as antiseize on the tip if too much was applied. I changed my COPs for precaution when I replaced mine with #140033-8 Accels for a little hotter spark. But that runs about $280 for the set. I was working steady so money was not an issue then.

 

Its 320 here for motorcraft, or the autozone brand... so it doesn't matter either way. From what I've read the COP's don't matter so much as everything else does.. when it comes down to brand.

I didn't replace the boots. I don't think it would be to much anti-seize because it appears to be doing it to the extent I notice it, when the truck warms up... so I'd say it may be the COP's causing issues. Either way next weekend I am removing the throttle body, cleaning the MAF, and the TPS down good, and as well as giving the TB a good cleaning. Going to replace the COP's as well then. If they doesn't fix my issue then I am going to I guess pull the plugs back out, hopefully they won't break, being they are only a week old, and have a fresh coat of anti seize.

If anyone has any other ideas throw them out here.