Strange misfire problem
06-19-2011, 12:57 PM
#1
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Location: East middle of no where, WV
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Strange misfire problem
I now have a '98 GT...that like to misfire at odd times.
When I start in first and floor and go through the gears, its fine. But say if I'm cruising down the road at 50 MPH in 5th gear (car has what I believe to be 4.10's) its fine as well.......until you get in the gas hard. Then it misfires, repeatedly, enough that I know it's doing it, but not enough that it throws a code, so no CEL light no flashing, nothing. It seems to happen under load in higher gears around 2500 - 4000 RPM, then its fine. I just replaced the fuel filter as of an hour ago and it has relatively new wires. I'm going to mist the wires with water tonight after dark to see if they arc just to be sure, same with the coils, which I believe to be stock, however dont wanna replace em if its not the problem. Any ideas other than what I have already stated would be an awesome help. Thanks in advance.
When I start in first and floor and go through the gears, its fine. But say if I'm cruising down the road at 50 MPH in 5th gear (car has what I believe to be 4.10's) its fine as well.......until you get in the gas hard. Then it misfires, repeatedly, enough that I know it's doing it, but not enough that it throws a code, so no CEL light no flashing, nothing. It seems to happen under load in higher gears around 2500 - 4000 RPM, then its fine. I just replaced the fuel filter as of an hour ago and it has relatively new wires. I'm going to mist the wires with water tonight after dark to see if they arc just to be sure, same with the coils, which I believe to be stock, however dont wanna replace em if its not the problem. Any ideas other than what I have already stated would be an awesome help. Thanks in advance.
06-19-2011, 10:12 PM
#3
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Glad, in a way, to hear that I'm not alone. The fuel filter did help a little bit. I misted the wires with water to try to get them to arc but no luck. That would have made it fairly simple. I'm going to start pulling spark plugs and checking gap and wear tomorrow morning when the engine is stone cold. If that turn up no luck I'm going to break down and put new coil packs in.
06-21-2011, 09:31 PM
#4
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For those who even noticed or cared about this thread, I fixed the problem! The driver side coil pack which I believe fires the the plug for cylinder #2 was barely sparking. With the car idling I could get the other to arc at more than 2 inches away.
However the terminal for cyl. #2 was just barely making a spark. So I did some coil pack swapping and fixed it. The car runs like a champ.....now I just need to get a new thermostat since my old one decided to play metal shredder and self destruct taking the rad. fan with it somehow.......
Anyway, to those who read this good luck fixing your misfire or helping someone fix theirs.
However the terminal for cyl. #2 was just barely making a spark. So I did some coil pack swapping and fixed it. The car runs like a champ.....now I just need to get a new thermostat since my old one decided to play metal shredder and self destruct taking the rad. fan with it somehow.......
Anyway, to those who read this good luck fixing your misfire or helping someone fix theirs.
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