Igniter issue?

[9sec240]

Vehicle: 91 w/ redtop swap. mostly stock.

Issue: Cyl 1 misfire once warm. #1 plug comes out nearly black. Runs perfect when cold but as soon as the coolant temp starts to come up it misfires.

Things I have tried:Plug change. still misfires (rules out plugs)Switching coils 1 and 2. still misfires (rules out coil)replacing fuel system with top feeds. still misfires (rules out injectors)Compression test good all 4 cyls warm and cold (rules out mechanical issue)Ohm injector trigger wire to ECU good / voltage check at injector plug good (rules out wiring issue)Swapped ECU (rules out ECU)

No matter what we do or change, it continues to misfire and turn the #1 plug dark. Swapping the #1 and 2 spark plug cleans up the black one and turns the white one black.

Is it possible the igniter is causing an issue with the #1 coil once the car (and electronics) get warm?

[Blown240sx]

it could the ignition map and fuel maps change dependent on temp so I guess it possible. You can use an Ignitor from Suzuki Side Kick, SR or Z32 ignitor but you must have the pig tails.

[9sec240]

Swapped to a known good igniter and still have the same issue.

Kind of stumped. We are going to inspect all the wiring to the #1 coil for issues and if nothing found, probably pull the valve cover and look for valve train issues.

[Blown240sx]

is it getting black like fuel black? If so it could be a cut in the wire for the main power or cycling ground. The ground would come off the ignitor and run to the coil pack the 12v is a white wire and a black grounding wire.