This topic contains 7 replies, has 3 voices, and was last updated by 
Billy 2 years ago.
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This vehicles has me stumped has a misfire on cylinder 2&4 switches coils and the misfire stayed with the cylinders on both. I have the trigger voltage and constant voltage and a good ground at the coils while it’s unplugged. When I plug in the coil I loose trigger voltage.I still have a ground a constant 12v while plugged in. This is the same case on both cylinders 2&4. I pulled up wiring diagrams and 2&4 cylinders trigger voltage pins are right next to each other @the PCM.
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Sorry for the horrible grammar at typed this on the bumper of this car in a hurry. The spark plugs are brand new and switched the with the coils also. It has me stumped.
Just spit balling here …
Possible fuel injector issue?
Possibly,I’m lost as to why the entire circuit works with the coil connector unplugged,then when I plug it in there is no trigger voltage there,it’s like when you put it under conditions to work the pcm stops sending the voltage to it.
Could be something with the crank / cam signals ?
Regarding the coil trigger connection/voltage, I believe the ECU grounds that wire to trigger the coil to fire, so when everything is hooked up normally, you should see no voltage. The voltage will occur only on an open circuit – I believe what you’re seeing is normal.
Since you’ve already swapped coils and plugs, I would move on to injectors as Richard suggested. First swap an injector from 2 or 4 with a good cylinder and see if the misfire follows. If not, check injector trigger signals with a noid light. And if the injector trigger signals are normal, move on to compression and leakdown.
Thanks for the help. I’m going back to look at the car today and will update. When I have the coil plugged in and remove it from spark plug hole I stuck my test light in and it doesn’t arc out against my probe. But on the cylinders next to it it will arc out. I’m going to check the injectors next. As far as swamping them I can’t unless I remove the intake and at that point I might as well replace them. I can unplug and check with a mood light today and update.
If you want to verify whether you’re getting spark, a spark plug tester is cheap from the auto parts store or Harbor Freight. However, fitting that between an on-plug coil and the plug is not always feasible.
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