I'd bet on a weak coil. The spring inside of the boot that transfers the electrical pulse to the plug can get awfully rusted and deteriorated. You may just need to replace the boots on one or all of your coils. Your cheapest option is to buy 1 coil boot and a can of dielectric gel. Squirt some dielectric into the boot, in the middle of the spring and seat it around each COP. Really if you just pull the COPs you can look inside the boot and see how much rust is in there. If you have a 5.4 the drivers side tends to get more water and mud up into the engine bay and thus falls onto the top of the engine and into the holes where the plugs and COPs lie (yeah, I'm bad with names of engine parts). Could be a bunch of rust on your drivers side COPs.
How many miles are on your truck? If it's over 60K you might want to pull out the plugs and check them too...but we all know where that can get you and if you're not getting any "random misfire" codes or that check engine light blinking on and off then probably not the plugs. Although can you trust the computer all the time??? NO...
You could always replace the entire COPs too; I found a whole set of new ones on ebay for around 100.00, for all 8! I waited for a couple of weeks to find the good price, but it can be done. Patience is key.
What is getting at me is you say this doesn't happen in cooler weather. At all????? I mean, it's 70 degrees F outside and you smash down the pedal and you don't get ANY missing? And then if it's 95 degrees F you do????? I will think about that and search for a few ideas. But let us know, cooler air and no miss at all above 2500-3000 RPM???
Last edited by xJimbos; 06-25-2010 at 08:36 PM.