91 GS-T Misfiring

[gcobb]

I was data logging and noticed a misfire. I looked at the logger and turned off each injector until I got to #4 and it made little or no difference. So I replaced the injector and it did not produce any results. When Listening to the exhaust, I can hear where it sounds like there are two intermittent misses. I bought plugs and wires previously so that doesn't come into play right now. I then bought a spark tester to put in the end of the plug wires, one at a time. at .010 and at .020 each fired consistant with the other. When I checked then on .030, #2 and #4 were intermittent. So I assumed it was the coil. I took the shortcut by not shelling out $191 on a new coil, so I picked up one at a salvage yard. I put it on and there was no difference.

I don't know what else it would be causing two wires to not hit like the others do unless it is a very odd cioncidence that I picked up a bad coil. Would this be ECU related? It didn't do this after I rebuilt the head and put it back on, but started when I was data logging it.

Any help would be appreciated.

Thanks,
Greg

[l_eclipse_l]

What do you have the gaps set at on the plugs?

[gcobb]

The plugs are a 6ES gapped at .032. I'm testing the spark before it gets to the plug at the end of the plug wire with a spark tester I got from Advance Auto. It was okay across all 4 until I got to the third step in testing. The plugs shows to be burning good and brown too.

Originally Posted by l_eclipse_l

What do you have the gaps set at on the plugs?

[crunchymilk55]

regap them at .028