the light came on friday on way home from work with tcs light. Drove it saturday short distance 3 miles and tcs light went off. Pulled codes today and got P0300,302,304,306 multiple random misfires . It seems to be running fine have not noticed any misfires. the only other the out of the ordinary was the drivers side rear door power lock wasn't working (locking and unlocking using power lock switch) the last couple days but today is working fine,dont know if related or just another problem. Erased codes after I pulled them and drove short distance 3 miles and runs fine and no check engine light yet. any suggestions. thank you
CEL light Codes P0300,P0302,P0304,P0306
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Those types of error messages sometimes occur when the battery is going bad.
You should check the battery clamps and cables too.
I got these same codes last week and fixed it by replacing the spark plugs. I think my problem was that 2 of the plugs were a little loose (hadn't backed out yet though). The other 4 were almost loose. The plugs needed replacing anyway because the gap was .055" (limit is .050") but I think the loose plugs were causing the misfire code. Runs a little better now and no codes.
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This should solve your problem. If not, check for a bad coil.
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Got acute onset of engine misfire and stumbling, and luckily I was just a block from home. ScanGauge gave DTC P0300, P0305, P0306, misfire on cylinders 5 and 6. I replaced the ignition coils on these cylinders to no avail. Thanks to my smart nephew, a certified mechanic, and his laptop OBD software, spark testers, fuel injector signal testers, et al. we were able to figure out the problem was in the Evaporative Emission Control System.
Specifically, the "EVAP Emission Purge Control Solenoid Valve," that sits atop the throttle body, just downstream from the throttle butterfly on my '02, was sticking. It is a needle and seat valve. Because the valve outlet tubing enters the intake manifold closest to cylinders 5 & 6 it was affecting these cylinders. Not sure why there was no P1456 code. Anyway we sprayed carb cleaner into the inlet and outlet, and shook the valve until the sound of the free needle could be heard. Once reinstalled, no stumble or misfire -- problem solved. I hope this helps others with a similar problem.
The lesson is that the cylinder misfire code may due to a problem not local to that cylinder, e.g. spark, spark plug, or compression, etc.
Specifically, the "EVAP Emission Purge Control Solenoid Valve," that sits atop the throttle body, just downstream from the throttle butterfly on my '02, was sticking. It is a needle and seat valve. Because the valve outlet tubing enters the intake manifold closest to cylinders 5 & 6 it was affecting these cylinders. Not sure why there was no P1456 code. Anyway we sprayed carb cleaner into the inlet and outlet, and shook the valve until the sound of the free needle could be heard. Once reinstalled, no stumble or misfire -- problem solved. I hope this helps others with a similar problem.
The lesson is that the cylinder misfire code may due to a problem not local to that cylinder, e.g. spark, spark plug, or compression, etc.
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Just to update a few details: The valve is actually bolted to the top of the intake manifold just downstream from the throttle body. The purge valve was sticking in the open position, allowing the fuel vapors to cause cylinders 5 and 6 to run rich. After cleaning, and before reinstallation, we cycled the valve open and closed by connecting it to the battery and made sure that we heard the valve clicking. The OBD software is AutoEnginuity's ScanTool : https://www.autoenginuity.com/products/scan-tool.html, which at $250, compares favorably to a decent hand-held scanner. My nephew has the enhanced version which allows one to turn components on and off in order to see changes which will indicate if they are functioning.
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Yes, it was amazing to see the before and after voltages on the oxygen sensors, and to see them adapt and change in real time to the now correct fuel mixture. Great software, but it takes some study and knowledge of the ODY emission control system, plus learning the software in order to understand how to interpret what you are seeing. The software is equivalent to what the Honda techs have. The service manual does a pretty good job of explanation -- before this event, my eyes just glazed over when I came to this section, but after reading it thru, I now see how you need to understand it and how a malfunction in a small component can cripple you.
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