Change the spark plug wires i had this happen i checked the wires seemed fine to the human eye then my friend put electrical tape around the boots to hold them tight on the plugs and the car had no more misfire, i found this out after i replace the spark plugs the rotor, cap, and fuel filter. Dang electrical system anyhoo this may be your best bet, other than that i have noticed this problem on cars with air pockets in the cooling system maybe you can burp it if this is the case.
