Check Engine Light Code P0300 On GM 2.2L and 2.4L

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36 Responses

  1. romone pinnock says:

    1991 Toyota Camry … i am experiencing a usage of too much gas intake from my car .. how do i fix this problem

  2. Can’t. Get a video. On how to remove a cylinder. Head off a 2006 chevy malibu 2.2enginei took all the bolts out. Will not budge

  3. Sandy says:

    I have a 92 Buick century,4 cylinder that misses, back fires, and has no power gong up hill, it will get downc to 30mph sometimes and sounds horribly.When I figure out,I will post on what the problem is

  4. dewain says:

    I was told today this will cost me
    $2500 to fix today. 50k miles! WTF. looks like a manufacturing defect to me,

  5. says:

    I recently bought a Saturn Ion 2006 with 187K. The check engine light came on a week after purchasing. I then noticed a blue color smoke come from the exhaust after starting it, just happened once. Today I pumped gas and was leaving the station when my car started to bog down and idle hard. I turned it off and tried again. A few hours later, it started to feel like the gas pedal wasn’t working right, then the reduced power light came on. I turned it off for 10 secs and tried again… didn’t help. It seems to run a lot harder and the accelerator isn’t getting better, help please!!!

  6. KSanchez says:

    I bought a one owner 2006 Saturn Ion with 188K. It’s a nice well taken care of car, I really liked it in the first few weeks. Then I started noticing problems. First, the check engine light came on, then the air bag light, I had an oil change and reset the computer. Now, each time I put in gas, once I start the car it will seem like it’s bogging down and will idle hard. I will push the accelerator to keep it from dying. Today I was leaving the gas pump when I pushed the accelerator as usual, but it acted like it wasn’t getting gas at all. A few hours later later, I noticed the accelerator was hard like it wasn’t working right. That’s when the reduced power light came on. I done the 10 second test like the manual said but it came back on when I turned the engine on again. It stays on now, it seems like the accelerator isn’t getting better. It runs rough too.

  7. Allen says:

    I’m a little bit confused. I see the article says 2005 to 2009 is the issue motors, but someone in the comments asks about a 2010 motor and you say refer to the article, so is the 2010 motor also an “issue”, in other words where does it end OR does it. I am looking at buying a 2010 HHR, but now I’m thinking maybe I shouldn’t? Please let me know ASAP anyone out there as I have a limited time to act on this vehicle…

  8. Shaun says:

    Here we go…. I’ve got a 2004 Chevy Malibu with the 2.2L. Car was running great, on my way to work one morning. Showed no signs of anything wrong or going wrong. Stopped at the store, car sat for about 15 minutes. When I started it back up, the check engine light came on, car idled very rough, & it sounded like it was missing really bad. Immediately shut it off, let it sit for a minute or so, then tried again. The car did same thing. Being only 20 minutes from I decided to try a limp it there. Approximately 5 minutes into the drive (at about 20 mph) I noticed a funny smell. I pulled over, as I got out of the car I heard what sounded like an exhaust leak. Looked under the car and noticed the bottom of my catalytic converter & the flex pipe were GLOWING RED! I immediately raised the hood to see the entire catalytic converter was glowing. The 20 minute drive to work from the store turned into an hour, as I had to pull over 3 times to let the CAT cool down. That all happened on a Friday morning. Once I made it to work the car sat for almost 3 1/2 hrs while making phone calls and doing research on the internet. When I started the car up to leave, it ran fine, GREAT, as if nothing was wrong… WTF? LOL took it to a friends house about 10 miles away, ran great. Messed with it a little, started it, shut it off at least a dozen times. Not one time did it act up. Took it to Auto Zone, they plugged into it, that’s when the “P0300” code came up (With a little further research, I discovered how popular that code really is) started the car to leave, it acted up again. At this point, traffic was to heavy to drive the car at 20 mph. Instead of causing an accident, I left it there for the night. Picked it the next day (Saturday) took it back to my friends house, spitting & sputtering all the way. Researched & tried to trouble shoot what could be wrong with it, nothing I did worked. I changed spark plugs, took apart & cleaned the entire air intake system, and Sea-foamed the intake system. At that time, once again, car was running great. Time for a test drive… Approximately 6 miles into the test drive, the car started acting up again. Once again, tried to nurse it back. Started smelling funny, pulled over to find the CAT, Flex pipe, AND the “long skinny muffler” that sits in the “hump” in floor of car were all 3 glowing red. Whatever was in the CAT got hot enough, melted & passed through the flex pipe, and ended up in the “long skinny muffler”. With more research, I figured the CAT was plugged because it got to hot & melted whatever is inside of it. Whatever that was got hot enough again to melt, pass through the flex pipe & end up in the muffler. In theory, if I removed cause of “back pressure build up” (the plugged up exhaust) the car would run. So… I took the entire exhaust system off the car. From the end of the Flex pipe, all the way to the tip of the exhaust. Time for another test drive, right?!?
    Took the car on the same exact route as I did Saturday night… Ran great! Sounded like it shoulda been in a dirt track bomber race on a Saturday night, but…. It ran GREAT! So, I start my drive home from the west side of Phx, to east side of Phx. The car drove fine, didn’t push it, stayed at 55, trying not to get ran over on the freeway. I would estimate, 30-35 miles into the drive, car starts acting up, check engine light comes on, and I start to lose power. Broke down on the side of a Phx freeway, I was out of options. We sat ( the car & myself) for almost 2 hrs before it ran ok again. Once it started, and seemed to be running ok, I took off. Made another 10 miles, then it let go again. This time sitting for almost 3 hrs before it started & ran ok. Eventually turning what should’ve been, a 1 hr, 40 minute drive. Into a six hr drive. I know it was long drawn out story, but I’ve tried to be as detailed as I could. I’m out of options, almost out of money…. I need help!!!

  9. TamayaTech says:


  10. Digital says:

    2008 Chevy Cobalt 2.2L – Did all the normal steps; moved sparked plugs, ignition modules & injectors to another cylinder and still a misfire on #4. Only thing replaced so far was the o-rings on the injectors. Checked for vacuum leaks and there are none.

    After the ignition and power steering recall replacement recently I had to replace the TCM after the transmission started acting up . There was a flutter shifting into overdrive and it wouldn’t stay unless I gave it a little kick. Since I didn’t have the time to work on it, I took it to transmission shop. The owner told me he was getting weird readings after forcing the TCC solenoid into overdrive. The trans was staying in overdrive, which meant no leaks in o-rings. Instead of trying to stick me with an $800 bill to replace the TCC solenoid, I suggested we get a TCM from the junkyard for $40. He couldn’t believe it solved the problem. I’m a tech guy and deal with computers all the time, however, they are little different on cars.

    Since there is no Ignition Control Module on this car and the plugs are fired by the ECM, I’m wondering what your thoughts are on that being the problem given the background of the TCM issue. An ECM from the junkyard from the same model car is $50. The ECM would need to be flashed with the correct VIN, if it solved the issue.

    Next step would be the compression test

    Any thoughts?

  11. Backyard Auto Mechanics says:

    Before you go spending lots of time and money….. change your AIR FILTER.

  12. Roger says:

    Just got my 2009 HHR fixed and here is what it was. Started surging, Service Engine Light came on and gave a P01100 code for Intake Sensor on front of engine so I bought new one and it ran good for about a week. Then Service Engine Light came on again and gave code P01100 again but lead to Intake and Exhaust Solenoids on top of engine. Bought and installed those. Ran fine for a day or two then while on a trip far from home at a station it started and killed. It would not keep running long enough to drive it. It was obviously missing. Had code reader with me and it gave codes P0101 and P0300. The P0300 is apparently a catch all code that GM must use for many things so it was very hard to pin it down. It did say something about “Air Flow or MAF” on my code reader. With just enough knowledge of auto mechanics to be dangerous I thought maybe it is the Air Filter since I had never changed it. Remember car is barely running and coughing and stumbling to even drive. I bought a new air filter ($12) and presto….. all problems solved. I had to clear codes manually but car is running like new.
    Like I said I just got done but I have all the faith in the world that the problem is fixed.
    Hope this info is helpful to others.

  13. Calvin says:

    I have a 2005 cobalt with a po300 code reading ! My car has a lack of power and you can smell it flooding . Can you give me any advise onto the problem?

  14. Gus says:


    When you wrote..” replace cylinder head and bad valves” you mean replace Cilinder Head Gasket & bad valves?


  15. Sam says:

    2006 Saturn ion P0300 bad idling and misfiring bad under load acceleration also good at steady speed
    any thoughts on what to look at next, replaced plugs swapped coil and checked all electrical connections

  16. Kent says:

    I have a 2001 grand am 2.4L that recently got new piston rings and timing kit installed as well as all gaskets, coil housing, coil packing, spark plugs, and even fuel injectors, as well as fuel pressure regulator. not too long after I got a PO300 code and I cant figure out, could it be timing if so how can I check the timing. or MAP sensor it does not have a MAF sensor, it idles rough a little bit after start could you help?

  17. bullworine says:

    for pontiac g5 if engine lights comes on and code reader says p0010 , it means chassis and body ground r not properly connected or grounded ….

  18. Will says:

    2009 hhr 300 code. Shows up only when I start the car. Puff of smoke from tailpipe.

  19. larry says:

    did i just leave 1

  20. mick says:

    2005 malibu, 2005, when engine is warm and not all the time, but temp guage just rises up past half, the engine will flutter at exhaust, loss of power, the cat was replaced. what do you think

  21. marissa says:

    i have an 2005 chevy cobalt and i was told it has low compression and this is after someone put something in my gas tank. The dealer ship is saying its probably my engine but they only looked at it for 30 mins. They claim there is nothing in my tank or lines. my car will start but just stalls right back out unless you hold the gas is the dealership right or is it something other then my engine.

    • Sam says:

      It would have to be something very bad in your gas to cause l;ow compression= very unlikely. Possibly diesel fuel in the gas could have caused that.

  22. Anonymous says:

    i have a 2005 cobalt and i was told it has low compresion after someone put something in my gas tank and the dealer ship is a joke. what is the problem. the dealer ship is jumping right to putting a new engine in. is their a cheaper fix

  23. anna says:

    Have a misfire on 1st cylinder..after I’ve changed the spark plug it went away for a few days but the check engine light came back on givong the same error. .it does it when its idle amd than when I take off..I’ve also changed seals suspecting a leak to the spark plug. .didn’t help.

  24. kike jr says:

    hi i have a 2009 hhr 2.2 with cylinder 4 mysfire replaced spark plugs,coil packs, may u please help me.

  25. ivory says:

    Wat could cause my 09malibu to misfire po300

    • ProTech says:

      A lot of things can cause that, and that depends on what engine you have. Could be anything from a bad spark plug or ignition coil, to a wiring problem.

  26. sparky7366 says:

    well this is all fine and dandy but your not addressing a po300 even on accel and no other codes stored so I would assume that according to the diagnostic trouble tree that should be addressed first – since it is the most common problem and then I would adress the other problems as far as at idle only