Misfire at idle
06-19-2016, 03:36 PM
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Staging Lane
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Join Date: Aug 2015
Location: Columbia, SC
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Misfire at idle 2000 trans am bolt ons and converter, dyno tuned
Car ran great no issues. got converter put in the trans, had a surging idle, took it to tuner and he explained it was actually the long tubes messing with o2 sensors still that he never played with values for on the initial tune.
He tunes the trans since converter is in there now while he is at it. Car is tuned on a friday, I drive it with no problems at all and surging idle is fixed it's perfect.
Wednesday comes along and I head to test & tune night. Make a few passes everything is good. Last pass I overrev in burnout box and spit the belt off without knowing it, make a full 1/8 mi pass before realizing what had happened, coolant gets up to 240ish degrees before I shut it off. Fill with water and start up, car starts misfiring like it has a trex cam in it and throws po300 for random/multiple misfire. Drove it around track a little put tires back on and headed home all seemed fine.
Oil pressure good, Coolant level stays same, oil looks good.. but now at idle (not all the time, seems like only after it heats up after being driven some) it will start to misfire and if I let it sit like that long enough it will throw po300.
My first thought was air leak of some kind but I can't find anything, I don't think it would be anything like plugs/coils/wires as I do not have any issues anywhere else in the RPM range. Car pulls good and has no problems it only acts up like this at idle. Could it be a tune issue? I drove it from that Friday to that Wednesday with no issues so I don't feel like the tune would have anything to do with it.
I hope I put this in the right section.. Thanks
Car ran great no issues. got converter put in the trans, had a surging idle, took it to tuner and he explained it was actually the long tubes messing with o2 sensors still that he never played with values for on the initial tune.
He tunes the trans since converter is in there now while he is at it. Car is tuned on a friday, I drive it with no problems at all and surging idle is fixed it's perfect.
Wednesday comes along and I head to test & tune night. Make a few passes everything is good. Last pass I overrev in burnout box and spit the belt off without knowing it, make a full 1/8 mi pass before realizing what had happened, coolant gets up to 240ish degrees before I shut it off. Fill with water and start up, car starts misfiring like it has a trex cam in it and throws po300 for random/multiple misfire. Drove it around track a little put tires back on and headed home all seemed fine.
Oil pressure good, Coolant level stays same, oil looks good.. but now at idle (not all the time, seems like only after it heats up after being driven some) it will start to misfire and if I let it sit like that long enough it will throw po300.
My first thought was air leak of some kind but I can't find anything, I don't think it would be anything like plugs/coils/wires as I do not have any issues anywhere else in the RPM range. Car pulls good and has no problems it only acts up like this at idle. Could it be a tune issue? I drove it from that Friday to that Wednesday with no issues so I don't feel like the tune would have anything to do with it.
I hope I put this in the right section.. Thanks
