So I bought the truck in December and it was misfiring when I testdrove it and the dealer said they'd fix it, but apparently they just made it quit long enough for me to hand over a check.

I have a 2007 5.4 F150 FX2 and it misfired at about 1800rpms and its more common when its colder out like under 40*. The cel will come on and flash but will go away, so its hard to get it checked. Eventually it stayed on and it came up misfire on #8, so I swapped the cop with #6 and when the cel came on again, it came up random misfire and on #5, #6, and #8. The plugs were nasty so I bought 4 new and put them in and I can tell it runs smoother, but I still get the misfire at about 1800rpms but the cel didn't flash this time. I've also had a fuel smell when I sit at a light and idle for a minute. I was gonna do cops next, but thought I'd post up and see if yall agree.

 

The gas smell may be from the plugs you installed not torqued down enough. I had the same issue after I changed mine. I also just changed my COPs because of a misfire at about the same RPM's. Everything is running good now. How many miles on your truck?

I bought my COPs here. http://www.ebay.com/itm/170958703728...84.m1423.l2649

Much cheaper than from the dealer.

 

The gas smell was there before I changed plugs and it has 150k on it.

 

I would do the other 4 spark plugs you did not replace and the COP's and see if that solves your problem.

 

that's what I thought, thanks for the help.