C5 Z06 Misfire/P0300 Code
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3rd Gear
Joined: Oct 2017
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C5 Z06 Misfire/P0300 Code
Hello All,
I recently purchased a C5 Z06 with a cam and some other modifications installed. It was originally tuned by A&A Corvette 10+ years ago. Here is the sale thread from the first owner (I am the third): https://www.corvetteforum.com/forums...-2002-zo6.html This problem seems to have developed during the second owner's ownership.
I keep getting a random P0300 code that lights up the CEL. Sometimes the CEL will flash indicating a misfire and sometimes it will just light up and stay on. What is weird is that the car runs great. It idles and drives fine and if the code wasn't there I would have no idea that something may be wrong. When the CEL flashes the exhaust note does not change and I do not notice any loss of power. I will say that the code only goes off when driving. However, I've had it go off when driving hard, around town, and while just cruising normally.
I have the Torque Pro app and I was using it the check the individual misfire counts. Cylinders 2, 6, and 7 do not seem to be having any misfire events. The other cylinders do have their counts increase especially cylinder 3. I checked these counts under Torque Scan and then [GM]Misfire Cyl..# (1-8) History [221201, 221202, 221203, 221204, 2211f8, 2211f9, 2211fa, 2211fb for Cylinders 1-8 respectively].
I have tried the following things per other threads on this issue:
- New spark plugs and wires (NGK TR6, Nology w/ covers installed)
- Coils
- Wire shorting on bracket at back of engine (Not close to bracket, no indication of wear)
- Injectors seem to be clicking after listening to them
I'm baffled by this code because the car runs great. However, since the car was professionally tuned and originally did not have this problem, I believe that something is going wrong. However diagnosing that issue is proving to be a challenge.
Any ideas on where I should go from here? Thanks for reading through this.
I recently purchased a C5 Z06 with a cam and some other modifications installed. It was originally tuned by A&A Corvette 10+ years ago. Here is the sale thread from the first owner (I am the third): https://www.corvetteforum.com/forums...-2002-zo6.html This problem seems to have developed during the second owner's ownership.
I keep getting a random P0300 code that lights up the CEL. Sometimes the CEL will flash indicating a misfire and sometimes it will just light up and stay on. What is weird is that the car runs great. It idles and drives fine and if the code wasn't there I would have no idea that something may be wrong. When the CEL flashes the exhaust note does not change and I do not notice any loss of power. I will say that the code only goes off when driving. However, I've had it go off when driving hard, around town, and while just cruising normally.
I have the Torque Pro app and I was using it the check the individual misfire counts. Cylinders 2, 6, and 7 do not seem to be having any misfire events. The other cylinders do have their counts increase especially cylinder 3. I checked these counts under Torque Scan and then [GM]Misfire Cyl..# (1-8) History [221201, 221202, 221203, 221204, 2211f8, 2211f9, 2211fa, 2211fb for Cylinders 1-8 respectively].
I have tried the following things per other threads on this issue:
- New spark plugs and wires (NGK TR6, Nology w/ covers installed)
- Coils
- Wire shorting on bracket at back of engine (Not close to bracket, no indication of wear)
- Injectors seem to be clicking after listening to them
I'm baffled by this code because the car runs great. However, since the car was professionally tuned and originally did not have this problem, I believe that something is going wrong. However diagnosing that issue is proving to be a challenge.
Any ideas on where I should go from here? Thanks for reading through this.
