Misfire-need some help

Ive got an 1989 Beretta with a 2.0 and have been having some trouble with a misfire. Car misfires at idle but is not a constant miss so I can't narrow it down to one cylinder. Will miss at cruising speeds and when accelerating if it hasn't warmed up all the way but goes away when warmed up. It wont set a C.E. light and no codes are stored. I have replaced and checked the following with no luck.
-Ignition control module
-Coils (swapped each old one with a new one and found no change)
-Plug wires
-Crank sensor
-Coolant temp sensor for ECM & pigtail connector
-Verified proper voltage at TPS sensor at idle
-I replaced the head gasket for a leak externally so I know no coolant is getting in cylinder. Plus head gasket leak wouldn't be noticed at cruising speeds. (unless it was dumping into cylinder)

If anyone has any idea it would be greatly appreciated.