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P0300 code diagnosing

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Old Dec 4, 2025 | 03:21 AM
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Default P0300 code diagnosing

Hi all! Im pretty stumped on this i may just take it to garage to be officially diagnosed. Unfortunately i like to try to diagnose thing myself to save on costs for others to look at it lol. But I just bought my 2001 zo6 with a stage 3 cam as I was driving it home it was fine until I was about 5mins from home. The codes it was throwing was p0300, p0153, and p1380. I just changed the spark plugs and i threw in some new premium fuel. When I spoke to the man I bought it from he said the car was sitting and on E and then he threw some gas in it. If anyone could help It would be most appreciated. If you need anymore info I can tell you whatever! Thanks again!

Edit: ive looked into the codes p0300 is a multiple or random misfire. So sounds like it could be anything. The p0153 is a o2 sensor. And p1380 is for the ebcm which im well aware of lol. Seems to be running rich so im not sure if it needs retuned or something else. Another this is that it jerks like crazy in 1st which could just be me not give it enough gas because it is supposedly a twin disk clutch.
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Old Dec 4, 2025 | 08:56 AM
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Besides the cam, what else has been done?
What tuning is it running?
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Old Dec 4, 2025 | 10:28 AM
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Assuming it was running fine before you changed the plugs the most likely thing is you didn't get one of the wires seated properly. They will sometimes pop back a little if you don't use enough lube.
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Old Dec 4, 2025 | 10:42 AM
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Moved to C5 Tech for more discussion.
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Old Dec 4, 2025 | 11:16 AM
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I'm wondering if whoever did the tune, and one had to have been done for a "stage" 3 cam, didn't tune out the random misfire part of the tune. I have never gotten those codes with my built LS7. BUT-When I hook up an old Predator hand held tuner/real time tuner, I get this message on it; Random multiple cylinder misfire, cause unknown. I assume the cause would be cam loping at idle. Never get any codes or check engine/MIL light. It may take several key ups to activate the MIL after it has been cleared. IDK enough about EFI.tuning to say for sure. Maybe someone else will chime in.
@the_merv
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Old Dec 4, 2025 | 11:38 AM
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Originally Posted by RAWZO6
Hi all! Im pretty stumped on this i may just take it to garage to be officially diagnosed. Unfortunately i like to try to diagnose thing myself to save on costs for others to look at it lol. But I just bought my 2001 zo6 with a stage 3 cam as I was driving it home it was fine until I was about 5mins from home. The codes it was throwing was p0300, p0153, and p1380. I just changed the spark plugs and i threw in some new premium fuel. When I spoke to the man I bought it from he said the car was sitting and on E and then he threw some gas in it. If anyone could help It would be most appreciated. If you need anymore info I can tell you whatever! Thanks again!

Edit: ive looked into the codes p0300 is a multiple or random misfire. So sounds like it could be anything. The p0153 is a o2 sensor. And p1380 is for the ebcm which im well aware of lol. Seems to be running rich so im not sure if it needs retuned or something else. Another this is that it jerks like crazy in 1st which could just be me not give it enough gas because it is supposedly a twin disk clutch.
Do some research in your service manual. I think the issue with jerking in first gear is contributing to the problem, and the P0300 and P1380 are related.
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Old Dec 4, 2025 | 04:35 PM
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DOUBTFUL a garage will be able to “officially” diagnose your concern…they just replace parts…P0153 is a “lazy” O2 sensor…as far as a random misfire other than changing all plugs and wires without some diagnostic equipment you will not be successful diagnosing this !!!

Last edited by C5 Diag; Dec 5, 2025 at 06:41 AM.
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Old Dec 5, 2025 | 06:37 AM
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Originally Posted by C5 Diag
DOUBTFUL a garage will be able to “official” diagnose your concern…they just replace parts…P0153 is a “lazy” O2 sensor…as far as a random misfire other than changing all plugs and wires without some diagnostic equipment you will not be successful diagnosing this !!!
I understand what you're saying. I'm going to try wires and a fuel filter today. To see if that does anything. I appreciate it!
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Old Dec 5, 2025 | 06:39 AM
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Originally Posted by grinder11
I'm wondering if whoever did the tune, and one had to have been done for a "stage" 3 cam, didn't tune out the random misfire part of the tune. I have never gotten those codes with my built LS7. BUT-When I hook up an old Predator hand held tuner/real time tuner, I get this message on it; Random multiple cylinder misfire, cause unknown. I assume the cause would be cam loping at idle. Never get any codes or check engine/MIL light. It may take several key ups to activate the MIL after it has been cleared. IDK enough about EFI.tuning to say for sure. Maybe someone else will chime in.
@the_merv
yeah i personally was trying to look into diagnosing it before i start throwing tons of money into parts at it. Im not entirely sure if the guy i bought it off of had a good tune on it. So I may just try to get it retuned. I appreciate your help!
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Old Dec 5, 2025 | 06:43 AM
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Originally Posted by Dads2kconvertible
Assuming it was running fine before you changed the plugs the most likely thing is you didn't get one of the wires seated properly. They will sometimes pop back a little if you don't use enough lube.
well it ran mostly fine once I bought it. But then it started doing that jerking in first gear so ive had it parked since. But the reason for that could be the bad gas in it possibly.
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Old Dec 5, 2025 | 11:23 AM
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Big cam, no tune, they run like crap. That jerking would be typical.
New plugs and wires is never a bad idea though.
Get the wires changed and see how it does.
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