P0300

Hey.. My roommate has an 05 Aveo and its throwing a P0300 Check engine light. I know what it is - Random misfire in multiple cylinders. And thats exactly what its doing obviously. I've looked online. People have changed the plugs & wires with no fix. I have not done this yet, but I plan on it tomorrow. 1 guy said he took it to the dealer, they cleared the ECU, and and all the sensors, and this fixed the problem, but I dont see that fixing it. I could be wrong, but I never heard of that fixing anything. Do you think this could fix it? If not, what else do you think that it could be. Any help is appreciated. Thanks!

How many miles? Mine did it at 34k and I changed the plugs. While in there I found a vacuum leak off of the plenum. Fixed that. The NGK V POWER plugs that were in it were completely worn down so that there was no longer a v in the firing electrodes. I put NGK Iridium plugs back in. Either plug is reccormended by the Aveo owners manual. When you find what it is would you post us back?

Yes reseting the ecu will fix this.. Ps. Dont forget the lights on

dear ser
i want the WIRING DIAGRAM toTransmission Range Sensor Circuit .my car aveo1.4L MODEL 2009 IT HAVE CODE P0705
THNKS

dear ser
i want the WIRING DIAGRAM toTransmission Range Sensor Circuit .my car aveo1.4L MODEL 2009 IT HAVE CODE P0705
THNKS

dear ser
i want the WIRING DIAGRAM toTransmission Range Sensor Circuit .my car aveo1.4L MODEL 2009 IT HAVE CODE P0705
THNKS


look go to the dealer with a baby car ask for the part and they will show you where it gose if you could get the part good luck

I was researching a similar issue with my car. It seemed to go hand in hand with the engine light coming on and the hold button flashing. Common hits seemed to hint towards the MAP sensor (manifold air pressure). In my case, a rabbit that took up residence on my engine block chew through the wires going to that specific sensor. I don't know what my code is, but that's my problem and I'll take it in for repairs soon.

My symptoms of sort were a rough start one moring, reving up and down twice, then running normally IMO. But those pesky lights came on. It still drives. Not that I've driven it more than down the drive and back. Might not be related, but I thought that I'd mention it. The wires are fairly obvious in my case, top of the block and centered. The vacuum hose below it, might not be, but can also cause this symptom (according to google hits).

Pesky rabbits.

could be misfiring due to bad valves which don't seal properly..are common.
does the misfire occur during uphill driving, wide open throttle, during warm-up, highway driving or decelleration?

Fire == fuel + oxygen + fire/spark

If any one leg is missing you'll get a misfire. Unfortunately with fuel and oxygen, if those are missing, the car wont start in the first place. If they handicapped it'll just run poorly. Most noticeable with a change in your MPG average. I was reading through my book to try and find the radio code and noticed that it recommends replacing spark plugs and spark plug wires at 60K.

If the car stutters, you're probably missing on just one cylinder. Spark plugs are the CHEAP fix, so IF you're just going to go the route of replacing individual parts until you hit the nail on the head, I'd start there. With multi port injection it could also be fuel injectors. When I bought my car one of the first issues I came across when searching the web was an issue with the fuel injectors on the '04 model. I have an '05 model.

Random misfire? That's a rough one to troubleshoot. My old pontiac had an issue like that just before the head gasket blew. But it had one cylinder that likes to foul the spark plug up pretty good. And over 100K miles on it. If it truly is random, it could be fuel injectors. I could be the fuel. It could be the air filter and air intake. Spark plugs are either going to work or not, they generally not going to randomly not work. Baring fouled up plugs or bad wires. Still the cheaper fix IMO.

If the valve isn't seating rght, that should be a bit more obvious. Poor gas mileage, and probably some smoke out the tail pipe. Maybe not enough to see from the driver seat. But enough to fail emission tests (required in a lot of states now).

-----

Back to the rabbit. The rabbit wasn't home at the second check. Me and a friend were able to bridge the gap in wiring to the MAP sensor. I pulled the ECM fuses (both of them) and left them out some thirty minutes or so. Put them back and started it up. It stalled the first start, then started the second and the codes cleared. I thought of just pulling the battery, but the radio needs a code by the looks of things and I didn't want to deal with that. I guess I'll never know my specific code. But not having to spend $100+ on rabbit food, priceless.