So I recently bought a 2004 Ranger Edge with the 3.0L in it, and for the most part it runs beautifully. However, I keep getting p0304 (cylinder 4 misfire) and a p0316 (misfire detected on startup) codes along with a slightly rough idle. I was only getting the codes on hot startups, and even then they didn't come around much. The plugs I just replaced with Autolite platinums, the wires test fine, they are fairly new Beldens. I cleaned the MAF with no change. While testing different things, I noticed that when sitting hot and idling for a few minutes, the misfire condition becomes noticeably worse, up to the point where it is a constant misfire and the CEL starts blinking. Rev the motor up for a minute, CEL goes out and it starts running smoother again. It is definitely not a complete miss, but it also isn't firing a strong as the other cylinders. I took it out for a short drive and afterwards the idle was smooth and there was no misfire, until it idled for a bit. This only happens when the truck is warm, it doesn't do it when cold. I checked the upper intake gaskets by spraying carb cleaner around the area but the idle didn't jump. There doesn't seem to be any other vacuum leaks. This truck only has 84,000 on it, and given that for the most part it runs fine I seriously doubt there is anything internal going on, especially because this truck has definitely been taken care of in it's life. Pretty much everything is in perfect shape. Anyways, this is bugging the crap out of me so any suggestions would be appreciated.