Misfiring while driving

Many things can cause this. In no necessary order, cause I'm typin' this on the fly... Is the check engine lite on? Does the exhaust sound deep and throaty or hissy? First, check the ignition system out as a whole. Plugs, wires, cap, rotor and ignition coil. Second, while the plugs are out of the cylinders are out of their holes, note the condition of the plugs that are exposed to the combustion chamber. Third, what kinda gas are you using? Fourth, try leaving the gas cap off and see if the problem goes away. Fifth, can you get a fuel pressure reading off the fuel rail? Sixth, have you checked the catalytic converter yet? Last but certainly not least, pop the air cleaner, open the throttle body all the way up and look down the butterfly valves...do you see just a dirty base or a pool of oil? Try those, they're the easiest, quickest and cheapest, not necessarily the problem. If all's well, get the fuel trims with a cheap scanner, both long and short term trims, they should be both at or near "0".