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Discussion Starter · #1 ·
My 2001 Eclipse has had a misfire issue for quite a few months now. I have replaced the plugs, wires, cap and rotor and it is still misfiring. Is this common and what is usually the issue?
 

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You're going to have to be more specific on what your symptoms are. What SES codes do you have? Any other symptoms? Did this start following maintenance like a timing belt change? etc. You should also probably list your trim level and any modifications you might have made.
 

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Discussion Starter · #3 ·
You're going to have to be more specific on what your symptoms are. What SES codes do you have? Any other symptoms? Did this start following maintenance like a timing belt change? etc. You should also probably list your trim level and any modifications you might have made.
 

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Discussion Starter · #4 ·
My car is a gt with the 5 speed and the 3.0, check engine light is on but I haven't gotten it in to check codes. It's very consistent at being inconsistent, as for symptoms it will cut power on hard acceleration, downshifting to go up a hill or around corners and some times just cruising. It has been doing this since I got it and it has no modifications.
 

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My car is a gt with the 5 speed and the 3.0, check engine light is on but I haven't gotten it in to check codes. It's very consistent at being inconsistent, as for symptoms it will cut power on hard acceleration, downshifting to go up a hill or around corners and some times just cruising. It has been doing this since I got it and it has no modifications.
First, buy a code reader, best tool you can buy if you are a do-it-yourselfer. Then get back to us with the trouble codes for further help. There is a number of possibilities, so having the trouble codes helps narrow it down. Worst case scenario is timing belt, could be something much simpler, like one of the upstream O2 sensors.
Anyway, welcome to Club3G!!!
 

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Discussion Starter · #6 ·
First, buy a code reader, best tool you can buy if you are a do-it-yourselfer. Then get back to us with the trouble codes for further help. There is a number of possibilities, so having the trouble codes helps narrow it down. Worst case scenario is timing belt, could be something much simpler, like one of the upstream O2 sensors.
Anyway, welcome to Club3G!!!
I had my codes read multiple times now and every time I get a P0300 random misfire code. I have but a multitude of cleaners through it including Seafoam and B-12. They help but not much. Again cap, rotor, plugs and wires were all replaced. I've had some people tell me a fuel blockage in my tank, a bad fuel pump, bad valves, bad injectors. It's to the point I'm just going to end up replacing all of those. Any feed back and or help is very appreciated.
 

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Those cleaners are snake oil with the exception of the fuel injector cleaners that you put in the gas tank which can help but its more like a multivitamin not a cure you feel me? I highly recommend the bluedriver, I have one and its great. I know it sounds unrelated but definitely check for vacuum leaks. If you can I'd go ahead and replace all of the skinny hoses since its so cheap, namely the ones from the egr. Are you able to post a video? Does it hesitate like that only under load or does it do it if you drop it in neutral and give it a good blip?
 

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Discussion Starter · #8 ·
Those cleaners are snake oil with the exception of the fuel injector cleaners that you put in the gas tank which can help but its more like a multivitamin not a cure you feel me? I highly recommend the bluedriver, I have one and its great. I know it sounds unrelated but definitely check for vacuum leaks. If you can I'd go ahead and replace all of the skinny hoses since its so cheap, namely the ones from the egr. Are you able to post a video? Does it hesitate like that only under load or does it do it if you drop it in neutral and give it a good blip?
It usually only does it under load. If it starts to misfire and then I put it neutral and rev it its still usually there.
 

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As in it still misfires/hesitates? It's been ages since I've worked with distributors but if its all new and you're certain the timing and all thats good I'd say for sure look at vacuum leaks particularly dealing with the EGR system. That one seems to be the common unexplained misfire when the obvious stuff has been replaced. Keep me updated, I'd be more than happy to provide further ideas. More importantly I wanna see you get back up and running at full capacity. Good luck brother!
 

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Discussion Starter · #11 ·
Dang, it's been a little bit. I've now had injector o-rings replaced and intake manifold gasket it helped but still misfires. The misfires are not as violent and after they were replaced I went about a good solid 5 days before it started misfiring. Something I should have mentioned is in the higher rpms it makes a sucking noise and cuts on power, is that due to a vacuum leak or is it something else? Again any feedback would be nice.
 

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Sounds like a vacuum leak, which could be causing your p0300. In addition to vacuum hoses, check mating surfaces like throttle body to plenum, and plenum to intake manifold.
 

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What is not commonly known is that a recall was posted for frequent PO 300 codes. After you've checked the recommendations from the others and make sure that there's no overall mechanical issue, you may want to call a dealership and ask them about reprogramming the PCM.
 
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