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First problem with the 2023 Z06.
Noticed the car, last three months not running right, not revving quick, real slow and actually would stop and then go?
Figured bad gas, maybe, ran the tank almost dry and filled up with 93 octane, as always, did the same, would not rev quick, slow.
The engine light finally came on, after three months of this. Car has 7,500 miles.
Dealer programmer read out:
PO300 Engine misfire detected
PO301 Cylinder 1 Misfire Detected
PO307 Cylinder 7 Misfire Detected
At least I know the problem now.
It's been at the dealership two weeks, the GM team they talk to say they have not experienced this before!
After two weeks the only thing they told my dealership is, maybe bad gas! I already eliminated this, I think?
The engine light is now "Flashing" instead of just on.
Well, anyone had this problem?
If GM cannot tell tell what steps to take, what now? The dealership already said the gas is fine.
Maybe start with new plugs? Sensors? LOL
Kinda worried.
First problem with the 2023 Z06.
Noticed the car, last three months not running right, not revving quick, real slow and actually would stop and then go?
Figured bad gas, maybe, ran the tank almost dry and filled up with 93 octane, as always, did the same, would not rev quick, slow.
The engine light finally came on, after three months of this. Car has 7,500 miles.
Dealer programmer read out:
PO300 Engine misfire detected
PO301 Cylinder 1 Misfire Detected
PO307 Cylinder 7 Misfire Detected
At least I know the problem now.
It's been at the dealership two weeks, the GM team they talk to say they have not experienced this before!
After two weeks the only thing they told my dealership is, maybe bad gas! I already eliminated this, I think?
The engine light is now "Flashing" instead of just on.
Well, anyone had this problem?
If GM cannot tell tell what steps to take, what now? The dealership already said the gas is fine.
Maybe start with new plugs? Sensors? LOL
Kinda worried.
let it sit at the dealer until they fix it The longer it sits the more likely you could lemon law it if it came to that. Understand you may not want to do that but having that as an option yields leverage.
Another option is to escalate to GM to get more eyes on it.
If bad gas is suspected, they should drain the tank and refill it rather than just letting the car sit. I know they’ll figure it out but they should start somewhere. Is the battery 100% charged? I realize this is a stretch, but my 25 won’t hold a charge above 2 lights on the accessory battery tender.
We just had a Z06 in with 1,3xx miles that had a intermittent misfire code for bank 1, cylinders 5/7 as well. There's also another thread in the C8Z discussion forum regarding the same issue, seems like it's fairly common.
Only misfired the first 15 seconds or so in open loop on the initial cold start - Z06 double fires the injectors for the first 60 seconds to warm up the cats .
Flashed the MIL but didn't permanently command the light but stored the codes.
GM has a generic TSB out there too.
Put fresh plugs in and it cleared up
Don't start them up and shut them off right away (and use quality/top tier fuel). And drive them hard
Thank you very much! It's been over two weeks and they just got permission from the GM team to change out the plugs.
Pretty slow! I should know if it is the plugs today. I'll give them your input, sounds like this is what it is!
I'll let ya know if this was the fix.
Also, "Misty", your chips might play out! LOl
Thanks!
Picked up the Z today. The new plugs did the trick! No engine lights, and it actually runs really good now.
I knew I had a problem, for almost three months, but no engine light. After the engine light finally came on, took it to the dealer, two and a half weeks later, they finally changed out the plugs.
Needless to say I'll be finding another chevy dealer to take care of me.
Thanks to all, for telling me about the plugs, after telling the dealership they finally ordered them and put them in.
Never had a vehicle stay at a Dealership this long.
My fault for not actually "screaming" at them sooner, to get it out! A Bad Scene! LOl
It's been at the dealership two weeks, the GM team they talk to say they have not experienced this before!
This is not true. What they are not telling you is they have seen these misfire codes many times before, but they do not know how to address this. In your case, a new set of plugs was the fix. In other cases, they do not know or are not admitting outright that the LT6 has issues that cause this.
The fouling of your plugs is linked to the problem that these engines tend to dilute the oil with fuel. Have you checked your oil level lately?
Picked up the Z today. The new plugs did the trick! No engine lights, and it actually runs really good now.
I knew I had a problem, for almost three months, but no engine light. After the engine light finally came on, took it to the dealer, two and a half weeks later, they finally changed out the plugs.
Needless to say I'll be finding another chevy dealer to take care of me.
Thanks to all, for telling me about the plugs, after telling the dealership they finally ordered them and put them in.
Never had a vehicle stay at a Dealership this long.
My fault for not actually "screaming" at them sooner, to get it out! A Bad Scene! LOl
I can be your new dealer. I have proven my ability to diagnose over a forum post. 🤣👊😜
You need to determine the true root cause. Plugs don’t just foul for no reason. Mitchell B made a great suggestion above. My C7ZR1 set these same codes. It was highly modified and saw track time. Turned out the previous owner installed plugs two heat ranges colder and a couple wires melted on the headers. Replaced the plugs with the correct heat range and the wires and she ran perfectly. I suggest you determine the true root cause before it happens again. Could be as simple as too many short run cycles, but it could also be something more significant.
when you drive it. Once warmed up, beat on it. 8600rpm several times. Can't putt around 3 4k rpm and not blow that **** out.
That's the issue with an engine like this. It's fouling plugs out because many of you guys aren't driving it the way it was designed. These are the issues you'll run into over time.
Was warned about that when I had mine by my buddy who builds hi po engines so I followed the advice and never saw any degradation over the year and half and 3500mi i had the car. Many were short trips but you need open the thing up.
when you drive it. Once warmed up, beat on it. 8600rpm several times. Can't putt around 3 4k rpm and not blow that **** out.
That's the issue with an engine like this. It's fouling plugs out because many of you guys aren't driving it the way it was designed. These are the issues you'll run into over time.
Was warned about that when I had mine by my buddy who builds hi po engines so I followed the advice and never saw any degradation over the year and half and 3500mi i had the car. Many were short trips but you need open the thing up.
when you drive it. Once warmed up, beat on it. 8600rpm several times. Can't putt around 3 4k rpm and not blow that **** out.
That's the issue with an engine like this. It's fouling plugs out because many of you guys aren't driving it the way it was designed. These are the issues you'll run into over time.
Was warned about that when I had mine by my buddy who builds hi po engines so I followed the advice and never saw any degradation over the year and half and 3500mi i had the car. Many were short trips but you need open the thing up.
100% agreed.....That engine needs to be given the beans at least once a drive. It's like buying a race horse and just walking him around by the bit. You got to let him run every now and then.
Wow, if this is actually happening, the LT6 engine is defected.
I'll be going to Spring Mountain in the next month or so, and will ask the instructors about this problem. Drove the Blackwing last month and they have a huge shop for both cars, mainly just changing out the tires! Lol
These cars get the hell driven out of them and they should know something about this, if its a major problem.
I hit a 4X4 block one night years back in my "99" vette, at 95 mph, it cracked the block! I didn't know it till I checked the oil, it looked like "peanut butter" all over the oil stick! Took it to the dealer and told me the block was cracked, they had to put a new engine in. I didn't have my night vision goggles on that night!
So, I'm going out to check the oil level, I hope I don't find peanut butter on the stick!! LOl I'm serious!
Hope it doesn't show low either, thanks for the tip Mitchell.
Wow, if this is actually happening, the LT6 engine is defected.
I'll be going to Spring Mountain in the next month or so, and will ask the instructors about this problem. Drove the Blackwing last month and they have a huge shop for both cars, mainly just changing out the tires! Lol
These cars get the hell driven out of them and they should know something about this, if its a major problem.
I hit a 4X4 block one night years back in my "99" vette, at 95 mph, it cracked the block! I didn't know it till I checked the oil, it looked like "peanut butter" all over the oil stick! Took it to the dealer and told me the block was cracked, they had to put a new engine in. I didn't have my night vision goggles on that night!
So, I'm going out to check the oil level, I hope I don't find peanut butter on the stick!! LOl I'm serious!
Hope it doesn't show low either, thanks for the tip Mitchell.
The “peanut butter” or chocolate milkshake as it is usually called is the mixture of oil and coolant. This should never happen! Fuel in the oil is more common as they coexist to a certain extent, although normally tiny amounts of fuel mix with oil from the combustion process. Excess fuel as suggested above is a real problem and in the extreme can hydrolock cylinders when the compression stroke tries to compress fuel to catastrophic effect. Please let us know what you discover.
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