HELP! check engine light p0300

i can't believe my luck with this mp3. everything was cool during the test drive, but the day after i buy it the bushings turn into disasters and now a check engine light.

the cel came up as a 'p0300 random misfire.' is this a common problem with the mp3? as far as i know, the only change under the hood was the previous owner removing his injen cai and reinstalling the oem air intake box. any thoughts?
 
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42k miles on the car.

it could be the plugs, but the code is for a RANDOM misfire and not a particular cylinder. if one plug was bad, then only one cylinder would be bad.
 
i've seen a kia that had 3 plugs all foul up and cause misfires at ONCE. it doesnt take much

I tried driving the car, it was about as fast as a lawn mower until it got new plugs.
 
interesting....

well i'll go through the car until i find it. i'll start with the airbox connections and then the plugs/wires are next.
 
tarmac and beer said:
interesting....

well i'll go through the car until i find it. i'll start with the airbox connections and then the plugs/wires are next.

was it a private sale or from a dealer?

check plugs and re-gap......so cheap to get new ones if you are going to take them out. $6-8.00.....

reset/clear ECU......
 
You guys want a good horror story? Here we go. February 15th, my girlfriend is on her way to work with our 2001 stock MP3. All of a sudden the check engine light is on and she's losing power, as if the engine couldn't breathe anymore. Towed at a nearby dealership, the mechanic there reads a (quote) "Problem with the spark plugs" as error code. He replaces the spark plugs and let the car go. The next day, my girlfriend is on her way again to work when the check engine light is on again! She tries to reach the dealership but as the whole car starts to shake and she cannot get higher than 1000 rpm, she has to stop and call for a towing again! The same mechanic diagnoses melted (yes melted!) catalytic converters (both of them), replaces them (had to wait until friday for that) under warranty and let the car go. The weekend goes by and we don't use the car much, almost no highway at all. On monday, while coming back from her work, my girlfriend sees the check engine light again! She manages to come back home in one pice. The same night I go on a little test drive while the light is still on and do a little speeding on the highway. Nothing happens. We agree the next day that I will drive the car to the dealership and try to experience the problem by myself while my girlfriend is following with a friend in another car. It doesn't take long until I lose power (exactly around 109 km/h, 3300 rpm) and the car starts to shake again. I slow down, but now the check engine light is now blinking and my "backup car" is flashing its lights furiously. I pull over the side of the highway and my girlfriend tells me that they saw fire come from the exaust pipe! A little shaken, I let the car cool down a bit and I slowly reach the dealership a few minutes later in one piece. It takes them until next tuesday (March first) to replace one melted catalytic converter again, the PCM and something called a Air pressure sensor or something like that. 10 minutes after getting the car at the dealership, my girlfriend is on the side of the road again, calling me for help with her cell phone! Now the car is again at the dealership and they want to keep it until friday. Anybody here has any clue of what is going on with this lemon? It has about 98000 km. Any help is appreciated, we need it!
 
Red Storm said:
You guys want a good horror story? Here we go. February 15th, my girlfriend is on her way to work with our 2001 stock MP3. All of a sudden the check engine light is on and she's losing power, as if the engine couldn't breathe anymore. Towed at a nearby dealership, the mechanic there reads a (quote) "Problem with the spark plugs" as error code. He replaces the spark plugs and let the car go. The next day, my girlfriend is on her way again to work when the check engine light is on again! She tries to reach the dealership but as the whole car starts to shake and she cannot get higher than 1000 rpm, she has to stop and call for a towing again! The same mechanic diagnoses melted (yes melted!) catalytic converters (both of them), replaces them (had to wait until friday for that) under warranty and let the car go. The weekend goes by and we don't use the car much, almost no highway at all. On monday, while coming back from her work, my girlfriend sees the check engine light again! She manages to come back home in one pice. The same night I go on a little test drive while the light is still on and do a little speeding on the highway. Nothing happens. We agree the next day that I will drive the car to the dealership and try to experience the problem by myself while my girlfriend is following with a friend in another car. It doesn't take long until I lose power (exactly around 109 km/h, 3300 rpm) and the car starts to shake again. I slow down, but now the check engine light is now blinking and my "backup car" is flashing its lights furiously. I pull over the side of the highway and my girlfriend tells me that they saw fire come from the exaust pipe! A little shaken, I let the car cool down a bit and I slowly reach the dealership a few minutes later in one piece. It takes them until next tuesday (March first) to replace one melted catalytic converter again, the PCM and something called a Air pressure sensor or something like that. 10 minutes after getting the car at the dealership, my girlfriend is on the side of the road again, calling me for help with her cell phone! Now the car is again at the dealership and they want to keep it until friday. Anybody here has any clue of what is going on with this lemon? It has about 98000 km. Any help is appreciated, we need it!
Um, holy crap dude, you might want to start your own thread on that note. That sucks man.
 
ok, changed the plugs (oem units, proper gap) and the cel is still coming on. i did find a f'ing mouse nest under the motor cover nestled among the coils. i think it might be possible the mice chewed on the coils or the spark wires.

how much does it cost for new oem coil units?

any other thoughts on the cause of the p0300 misfire code?
 
Well, can you see any visible damage on your plug wires? I would remove them and check the resistance with an ohmeter. I wouldn't doubt it if they were chewed at, mice'll chew anything.

That's insane that you had mice there in the first place though! (boom01)
Wouldn't they get cooked on that valve cover?

I'm not sure how much the coils are, but I would test the wires first since I have a feeling they are cheaper to replace.
 
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the oem coil packs cost 27$ for both, or around that. not sure about the wires.

The car must have been sitting for a good amount of time.
 
I don't know if you read my thread before but I had the exact same thing.

1stly, my sparkco wires were corroded inside and the rubber boot became brittle and broke off.

2nd, 2 of my spark plugs had almost no electrode left. Changed them.

3rdly, and this is the final repair, the resistance of both coils were measured and I found that they both held 9.2 kohms (according to spec). But then they went crazy. It basically was unstable. I changed both of them and haven't got the p0300 code for 2 weeks now.

Hope that helps.
 
mp3 are fun :( haha

i ordered the new coil pack assembly from rosenthal ($23.65). i didn't order the spark wires yet; the guy at rosenthal wasn't sure which wires it needed. does anybody know how much the spark plug wires cost for the mp3? from memory, only the left and right cylinders use the wires.
 
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