96 2.7 P0304 Cylinder 4 code

Need some help guys. My truck is a 96, 2.7, 197k and yesterday my CIL came on and it was running ok. About 5 minutes later it started running really bad and losing power. Then it went into limp mode and I got off the road. I was still about 15 miles from home. My wife brought me my code reader and it was P0304 (cylinder 4 misfire). Ended up getting it towed home and today I replaced the plugs, wires, distributor cap, and rotor button. Same result. It will start but won’t idle and run horribly. Same code comes back. It does have a strong exhaust smell during running for a very short time. When cranking over it isn’t as smooth as it usually is. Cranking over it sounds like it’s out of time or something. I’ve read up on this code and seen also besides things I’ve already replaced it’s possible it’s a head gasket or valves or even fuel injector. I have not checked compression, I don’t have the tool to do that yet. I am mechanically inclined. I’ve had the head off twice replacing gasket for oil leaks and did my own regear job. Just need opinions on a direction to go. Any advice would be much appreciated.

 

@Taco critter