I have a 1990 3VZ pickup with a weird spark issue!!: Good spark on cylinders 2, 3 & 4. No spark on cyl 5. cyl 1 and 6 - will spark once when cranking than no spark! (strange I know). Changed coil, cap and rotor, igniter has been changed as well. Grounds cleaned. Distributor pick up coils measure perfect with ohm meter. checked pickup coil gap in distributor. distributor shaft bearing seem good (did not pull out distributor though) If you check spark out of main coil lead - the spark is not consistent - sparks, then a little pause, then sparks again. I used the FSM to go through all the ECU connector tests - all are okay. So I suspect the ECU. Just wondering if I am missing something before i go buy another one. Thanks!