Code PO300
Code PO300 Hey guys. I was driving back the other night from out of town. My rpms started going up and down and the car started losing power. I got off on an exit and pulled into a gas station. Car idled fine and even revved up fine. When I put it in gear and tryed to drive it started running rough as hell like it couldn't even go. I ended up having it towed to my place. The oil, water, and tranny fluid are fine.
The code reader shows a code PO300 which means "multiple engine misfires". I have no idea what could be causing it. I originally thought the MAF had gone out and it would show that on the scanner. But it must not be the MAF. I also got a code PO150 which means "high voltage" to the O2 sensor. My rear O2's have been removed and the codes programmed out. Does anyone have a clue where to start on this car or what could be causing the PO300 code? I wouldn't think that O2's would cause engine misfires. But maybe that is the problem. The car has had new Taylor wires and plugs put in it about a year ago. It has ran fine up until the other night. The wires look fine and unblemished.
Thanks.
The code reader shows a code PO300 which means "multiple engine misfires". I have no idea what could be causing it. I originally thought the MAF had gone out and it would show that on the scanner. But it must not be the MAF. I also got a code PO150 which means "high voltage" to the O2 sensor. My rear O2's have been removed and the codes programmed out. Does anyone have a clue where to start on this car or what could be causing the PO300 code? I wouldn't think that O2's would cause engine misfires. But maybe that is the problem. The car has had new Taylor wires and plugs put in it about a year ago. It has ran fine up until the other night. The wires look fine and unblemished.
Thanks.
Check here for more info and troubleshooting info for the P0300 code:
http://www.gearchatter.com/viewtopic8732.php
The O2 readings are hosed because you're misfiring, and therefore your exhaust is going to be wicked rich...
Check your spark plug wires, make sure your plugs are tight, and check your PCM bulk harnesses for water damage... all things I've personally experienced throwing misfire codes.
That should get you started. Good luck! Let me know if you have any questions.
-Eagle
http://www.gearchatter.com/viewtopic8732.php
The O2 readings are hosed because you're misfiring, and therefore your exhaust is going to be wicked rich...
Check your spark plug wires, make sure your plugs are tight, and check your PCM bulk harnesses for water damage... all things I've personally experienced throwing misfire codes.
That should get you started. Good luck! Let me know if you have any questions.
-Eagle
Ok everybody I'm updating. I hadn't messed with the car since I posted this thread. Well I go out this week to crank it and the battery is COMPLETELY dead. I mean not even the lights had a glimmer. Well I had it charged and put it back in the car. Well I cranked the car up and it idles fine. It will even rev up fine. I was wondering about the alternator but the battery light is not on and the volt gauge shows charging just fine. Well with the car idling fine I decide to try and drive it through my complex. As soon as I get backed up out of my parking space it starts bucking and won't hardly run. Then when it starts running rough it runs and idles rough from then on. Its almost like if I just leave it in park and let it idle then the car is fine. Its when I put it in gear that all hell breaks loose. Any ideas?
TECH Enthusiast
Joined: Oct 2002
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From: NJ
Just for the heck of it, check with a scanner to make sure your o2 on one side isn't flatlined. Had a very interesting occurance yesterday with my car and the LM1 WBo2. It was supposed to similate nbo2 and for some reason flat lined while my passenger o2 was working fine. Car flipped out and wouldn't run and p0300 flashed on my dash. Limped it back home.
Restarted it and boom the wbo2 started working and car ran again.... F'n weird,... and scary!!
Restarted it and boom the wbo2 started working and car ran again.... F'n weird,... and scary!!
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Just updating guys. Evidently there was some water or moisture somewhere. Must have gotten it blown away or it dried up. Don't know for sure. The codes are gone and the car runs fine. Who knows. At least it wasn't something expensive.
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for now it runs fine....was it raining or damp that day? Plugs, wires, coil, injectors..all the main culprits. These cars dont all the sudden throw a miss fires code and heal themselves. just my 2 cents...
