I have a weird problem with my 2004 F150 which is driving me nuts!
A couple weeks ago the CEL came on and I pulled the errors immediately.
I had a P0307, P0308, P0300 and P0316.
Since I didn't know when the previous owner changed the spark plugs, I changed them with Motorcraft SP515. He had Champion plugs in there and since they are known to cause misfires in this engine, I was hoping for the best.
The truck ran much smoother after that and the mpg went up.
Unfortunately, the CEL came back on later that day and I thought it might be the COPs.
I switched 7 to 5 to see if the error would follow. Well, it didn't...

Then I started thinking that my exhaust valves were toast.
The weird thing is, that the truck runs great and doesn't hesitate or stutter at all. It idles a little rough, that's it.
I decided to put some injector/valve cleaner in the tank, hoping that it might be a dirty injector.
Well, the CEL didn't came on for a couple days and I thought that it fixed the problem.
When I started the truck two days ago, the ****** CEL came back on with the codes P0308 and P0316.
I drove it to work without any problems and after I got home, I cleared the codes.
Yesterday I didn't have any problems with the CEL.
Today I started the truck, drove like 20 miles, shut it off for like an hour and when I started and drove it for like 2 minutes, that effin CEL came back on with P0307, P0308, P0300 and P0316.
I am at my wit's end and am already thinking about selling the truck.

Do you think it might really be the exhaust valves? Wouldn't burnt exhaust valves always cause trouble and not every once in a while? Also, wouldn't the truck run like **** with bad valves?

 

https://www.f150online.com/forums/v8...rror-code.html

I did some digging for you bud. I'm not mechanic but I'm wondering if it is this.

P0316 is a misfire and is p0300.

The other two codes correlate to misfires of cylinders 7 and 8. I'd check the COP boots first. Check if any are cracked or discovered. They are cheap to replace

 

Thanks for the link but I think that's not the case with my truck.
I forgot to mention that I also changed all boots when I changed the spark plugs. Also, I've changed the fuel filter and cleaned the MAF.

 

All your cops may be starting to break down.

 

Shouldn't the error follow though when you switch the cop from the misfiring cylinder to another?
In my case it didn't...

 

I have an 08 limited, 84k miles. factory plugs and cop's. its a 5.4....randomly i will get a misfire but the truck was always driveable and it would go away....but today it was really bad to the point where my cel actually came on - this was the only time i was happy to see the cel because now i have some kind of code to throw me in a direction of troubleshooting.i planned on doing the plugs this upcoming weekend as well as the cop's. but anyway the code was misfire cylinder 2. so i got home, swapped cop's, ran truck for a lil and No new code....so i said screw it, let me change the plugs. i had previously ran 2 tanks of fuel with seafoam. i replaced all plugs with motorcraft plugs, put fresh di-electric grease in all the boots, anti-seize on the shaft of the new plugs. All (factory) 8 plugs came out like butter, once i broke them loose from being torqued by factory, i did the rest by hand. but all in all, misfire was gone. I was amazed. but i still am going to change the cop's.

 

i know you said you did the plugs, but if you havent done the cop's yet, i would try that before anything else. if it is throwing a misfire, new plugs right outta the box can be bad too..