help random misfire
01-25-2009, 01:34 PM
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help random misfire Ok heres the story, i took my car to the wash to get all the road salt off the car,(drive thru undercarriage wash) so im in there getting washed and the idle starts getting rough (no problem it always did in the drive thru) so i drive off and it goes away like every other time BUT....now any hill under light throttle bucks a little so i press a little more on the pedle and it drops in passing gear i hold steady for like 2 seconds and it clears up and takes off. so its friday 01/23/09 lunch time at work and i start the car ses light is flashing random misfire is on the code reader so i take it home to try to fix it, no luck. heres what ive do thus far.....checked all connections to all sensors, removed icm and coils. coils are .7 or better checked all plug wires no burns. so what i want to know is or what im thinking is some how water got some where and is goofing things up like crank sensor or cam sensor any help to keep this poor boy out of the dealer would be great thanks.
01-25-2009, 01:46 PM
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unplug all plug wires make sure they're dry. Get some di-electric gel and put some in each end of each wire. Plug them back up. If you have long tubes make sure your o2 sensors are tight. Check the o2 connections for water too. I had a problem like this before after cleaning under the car and it fixed my problems. Never has come back.
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01-25-2009, 05:16 PM
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I did change all the plugs and it fired right and idles perfect now but under load it still throws the random misfire code. the passenger side plugs were all gas and wet looking the driver side was dry if that sparks someones mind let me know?
01-25-2009, 05:41 PM
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what code did your car throw?
Your front o2's essentially tell the engine how to run based on analyzing the exhaust gases. If your o2's are messed up, they will more than likely be sending the wrong signals back to your PCM, which in turn will cause it to run horribly wrong on one or both banks. This could explain why one bank of spark plugs had a shitload of gas on them. I think there's a good chance that if you replace your o2's you'll fix the problem. Just my .02
01-25-2009, 06:27 PM
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It was P0300 Random Multiple Misfire. For me it was caused after my header install.
Your front o2's essentially tell the engine how to run based on analyzing the exhaust gases. If your o2's are messed up, they will more than likely be sending the wrong signals back to your PCM, which in turn will cause it to run horribly wrong on one or both banks. This could explain why one bank of spark plugs had a shitload of gas on them. I think there's a good chance that if you replace your o2's you'll fix the problem. Just my .02
Your front o2's essentially tell the engine how to run based on analyzing the exhaust gases. If your o2's are messed up, they will more than likely be sending the wrong signals back to your PCM, which in turn will cause it to run horribly wrong on one or both banks. This could explain why one bank of spark plugs had a shitload of gas on them. I think there's a good chance that if you replace your o2's you'll fix the problem. Just my .02
01-29-2009, 08:10 PM
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have not started the car till today to see if it still would idle and it didnt! wtf!!!! i didnt change the wires yet but thought it should still idle......
01-31-2009, 01:16 PM
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ok changed all wires and now it idles till it warms up, then it revs up and down (once it warms up) and i got two codes random misfire and o2 senser circuit malfunction. i now have one question what side is bank 1 and what side is bank 2? my car is 98 v6 3800 series 2 thanks (going to get an o2 senser)
02-01-2009, 08:59 AM
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got o2 sensor, going to put it in the guy at the auto store said if its bank 2 sensor 1 its a downstream o2 sensor dont sound right to me what do you all think?
02-01-2009, 09:12 AM
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Dude, I was throwing random misfire codes too, it ended up being water in the connection of the driver side 02 sensor. Where the 24" extension plugged into the 02 sensor, there was maybe a few drops of water, lol. Just enough to **** my week up and make me buy new plugs/wires for no reason.
I bought 2 new 02 sensors, unplugged the driver side one, found the water in the connection (it was green, iirc, lol), blew it out, plugged it back in and the car ran perfect, lol.
Good luck dude, hope you find it.
I bought 2 new 02 sensors, unplugged the driver side one, found the water in the connection (it was green, iirc, lol), blew it out, plugged it back in and the car ran perfect, lol.
Good luck dude, hope you find it.