Sounds like it's missing at idle speeds

[runawaygun762]

When I first start the truck, it sounds like it's at a high idle, after it warms up, it kinda sounds like it's missing. if I'm at low speeds and not on the gas at all, it sounds like it's missing, or a real slow idle, kinda like a drag car with it's stroked motor. Real slow, almost like you can count the cylinders firing. But in "Drive", at a stop, it goes back to a normal sound. Do I need to get a cylinder compression check done? Could this be a bad head gasket? It's an '02 F350 with about 260k on it, if that helps. Thanks guys.