2002 Trans Am Code P0300
09-22-2013, 09:18 PM
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2002 Trans Am Code P0300 Car is running rough after it warms up for a minute. I get the flashing SES light. Had it checked at AutoZone and that's the code that was pulled. But they never gave me info which cylinder I'm getting the missfire. Funny thing is this all started while driving in the rain. First time I ever drove it in the rain since I had the car. Car has 73K miles. My thinking is it could be plugs and wires but I know there could be an assortement of different things that it could be. Any thoughts?
09-23-2013, 02:44 AM
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Well, I'm getting that rough idle all the time. It just started all of a sudden during heavy rain but it's still doing it now in dry conditions. Car had headers installed about 7-8 months ago.
09-23-2013, 10:49 AM
#6
Rain would not effect your coils unless you got water into the engine bay.
I suspect its your O2 sensors. When they get wet with headers, I have seen certain brands act funny especially if using O2 extentions.
Before you start buying unecessary parts. You need to data log the car to see. If you have Hptuners or EFI Live, or take it to a tuner. They should not charge you much for a scan.
I suspect its your O2 sensors. When they get wet with headers, I have seen certain brands act funny especially if using O2 extentions.
Before you start buying unecessary parts. You need to data log the car to see. If you have Hptuners or EFI Live, or take it to a tuner. They should not charge you much for a scan.
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09-23-2013, 12:10 PM
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What's odd is that it runs great for about 2 minutes or until it warms up. I can park it for 15 minutes and the same thing. Yes, I don't want to buy a bunch of parts that are unecessary. So will a scanner say if I have a bad plug or a coil o ran 02 sensor?
09-23-2013, 12:13 PM
#9
Typically random misfire is something in common with all cylinders, if t was ignition related it would list a specific cylinder...I would suspect crank or cam sensor/wiring if hard to start..put car on a scanner and look at the o2 readings it might give some insight into the issue
09-23-2013, 04:21 PM
#11
I have seen this occur several times especially after rain.
I understand that if he disconnects the O2's all the car will do is stay in open loop but he needs to let it go into close loop to see how the O2's are switching or if they are active at all.
This is why data logging looking at fuel trims, O2 activity, and more will help accurately find the problem vs. just buying parts hoping to stumble on the solution.
I understand that if he disconnects the O2's all the car will do is stay in open loop but he needs to let it go into close loop to see how the O2's are switching or if they are active at all.
This is why data logging looking at fuel trims, O2 activity, and more will help accurately find the problem vs. just buying parts hoping to stumble on the solution.
09-23-2013, 05:46 PM
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09-23-2013, 08:53 PM
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Rain would not effect your coils unless you got water into the engine bay.
I suspect its your O2 sensors. When they get wet with headers, I have seen certain brands act funny especially if using O2 extentions.
Before you start buying unecessary parts. You need to data log the car to see. If you have Hptuners or EFI Live, or take it to a tuner. They should not charge you much for a scan.
I suspect its your O2 sensors. When they get wet with headers, I have seen certain brands act funny especially if using O2 extentions.
Before you start buying unecessary parts. You need to data log the car to see. If you have Hptuners or EFI Live, or take it to a tuner. They should not charge you much for a scan.
09-29-2013, 05:27 PM
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Ok, haven't really had any chance to work on the car this week. I did drive it today and decided to go ahead and drive on the highway a bit. Once I drove for a few more minutes the car started driving like there was nothing wrong, well almost nothing, I could notice may an ever so slight miss and maybe not quite the power I have been having. But once I parked the car for a few minutes, it started all over again and once again smoothed out and driving fine again. Does this new info help in any way? I will finally get it on a scanner to check and see exactly what's wrong but just wanted to see if you guys had any more insight. Thanks.
09-30-2013, 10:19 PM
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if you had a coil problem it would be one specific cylinder. I would probably look at the 02 sensors as well. You can pull the sensors after it warms up and see if it smooths out. If it does it a pretty good sign that it is the o2 sensors. If not then it is probably something mechanical. Just my 2 cents