Why is my truck misfiring so bad without plug, wire, or compression problems?

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98 yota 2.4l 190k mi. 5 spd. Truck started misfiring real bad every time I hit the gas. Autozone diag says it's a misfire on cyl 4. changed all plugs, checked all wires by swapping and trying to get the misfire to follow a certain wire, checked compression and it was fine, (even a little high). Plugs and exhaust smelled like gas. Could it be valves? Fuel injector?