Cylinder Misfiring - Service Question

[UNH70SS]

Help!

I have a 2014 ZL1 unmodified automatic with ~6,000 miles.

This past Thursday, I took her out and the check engine light came on along with the Service Stabilitak indicator. Also, she was running very rough. I've had her out a few times this summer with no prior issues. The car is basically in mint condition.

I brought her into the local dealership for service. They got back to me and said that the Stabilitak issue was likely solved through a software update but they won't know till they put some miles on it.

They said that when they scanned the check engine light it was indicating that one of the cylinders wasn't firing properly. They said they swapped plugs and wires and it didn't help them diagnose the issue.

Their next step is to tear down the motor but they have several vehicles in front of me and can't get to it until next week the earliest.

I'm wondering what my options are at this point. I contacted another dealer and they are looking at roughly the same time frame, but their service center is much larger, and they have Corvette technicians in house so I'm thinking that may be a better place to bring it to. I would likely have to have it towed from one dealer to the other.

[tartagliazl1]

could be as simple as a cracked plug. or a bunt wire.

[UNH70SS]

Originally Posted by tartagliazl1

could be as simple as a cracked plug. or a bunt wire.

That's what I'm hoping but they claimed they moved plugs and wires around and it continuously showed the same cylinder as being the culprit.

[AlisoBob]

Dealerships are idiots. Could be a coil, or fuel injector, or harness plug. All simple stuff. DO NOT let them tear into your car.

[gtstorey]

Could be a coil or injector problem. This needs a lot more diagnosing before they start tearing into the engine. Even if everything else checks out, they should start with a compression and leakdown test before tearing into anything.

At 10 years and 6000 miles, I would be very surprised if it's internal engine problems. Unless those 6000 miles were in year 1 and it then sat for 10 years.

Find a better mechanic.

[tartagliazl1]

Originally Posted by UNH70SS

That's what I'm hoping but they claimed they moved plugs and wires around and it continuously showed the same cylinder as being the culprit.

did they happen to tell you what cylinder it was? If i where you i would take it home and do all the easy stuff first. Check plugs, wires, coil harness. fuel harness. Mice love electrical wire if it sat for a while before you bought it.

[UNH70SS]

Originally Posted by tartagliazl1

did they happen to tell you what cylinder it was? If i where you i would take it home and do all the easy stuff first. Check plugs, wires, coil harness. fuel harness. Mice love electrical wire if it sat for a while before you bought it.

Thanks. I think I'm going to go pick it up tomorrow. I was referred to a mechanic in town that might be a better option.

[ZMEnow]

Originally Posted by UNH70SS

Help!

I have a 2014 ZL1 unmodified automatic with ~6,000 miles.

This past Thursday, I took her out and the check engine light came on along with the Service Stabilitak indicator. Also, she was running very rough. I've had her out a few times this summer with no prior issues. The car is basically in mint condition.

I brought her into the local dealership for service. They got back to me and said that the Stabilitak issue was likely solved through a software update but they won't know till they put some miles on it.

They said that when they scanned the check engine light it was indicating that one of the cylinders wasn't firing properly. They said they swapped plugs and wires and it didn't help them diagnose the issue.

Their next step is to tear down the motor but they have several vehicles in front of me and can't get to it until next week the earliest.

I'm wondering what my options are at this point. I contacted another dealer and they are looking at roughly the same time frame, but their service center is much larger, and they have Corvette technicians in house so I'm thinking that may be a better place to bring it to. I would likely have to have it towed from one dealer to the other.

Run, and I mean run fast!! There is nothing in the engine internals that are going to stop the cylinder from firing if your plugs, wires, coil packs are all functioning except a bad injector, because if all those are working it’s gonna fire. If you had dropped a valve you would know it. The question is it not firing properly or not firing at all.

I would go to the corvette guy as he is a certified performance tech which is the only guy that should be working on your car. By the way there are a ton of things that trigger stabilitrak as it’s sort of a limp mode for protection.

Don’t know your ability but I know so many people who take their vehicles into Chevy dealers for a tune up and come back with intermittent misfires which are either the new plug wires they put on which they didn’t push all the way on or in a rush they cracked a plug or in some cases both.

I would get my car out of that dealer for you have some real problems.. take home take your time and at least identify the misfiring cylinder and then focus on that, or take it to the performance tech.. best of luck.. sucks not having the ability to,do it yourself..

[morepowerjoe]

I agree with everything that the guys said. I suggest taking it to a good local shop where they work on performance gm vehicles and have them do some basic diagnosing on the plugs, wires, coils, and injectors. Oh and make darn sure you battery is in good shape, if there's even a question about it get a new one.

[NZZL1]

Originally Posted by morepowerjoe

Oh and make darn sure you battery is in good shape, if there's even a question about it get a new one.

If your 2014 has never had a replacement battery, then this is the most likely cause.

The messages "stabiltrak, reduced power, check engine" are normal responses to a fault condition but they are a "catch all" response. To diagnose the fault, any decent vehicle service business uses professional scan tools to extract the DTC codes and information from the service manual to test signals at various points in the electrical system. Jumping to the conclusion of "tearing down the engine" is crazy, and smells of a scam.

These messages can be due to a faulty ECM, TPS on the throttle body, or on the accelerator pedal, and many others. All of these faults are not uncommon, but an aged battery is most common.

[silversleeper]

I agree with everyone. A very low mi not mod car LSA engine is unlikely to have some major problem with one cylinder. I could only imagine a rare case of coolant issue overheating the rings in the passenger rear but yep as everyone said it is much more likely something cheap and simple. Just needs proper diagnosis.

The stabilitrac comes on when so many things happen that isn't anything about stabilitrac. If someone in the car in front of you farts that light comes on. A low battery and stuck injector from not running it can be causes. LOL cue the mechanic with pliars going out tapping on things to fix them (injector of misfiring cyl).
Sometimes bad mechanics break as much as they fix so I'd go somewhere else that has a very good reputation. An average mechanic might cost you more than the dealer at this point.


I'd go for a new battery if the other one is several years old because of lack of driving and these cars seem sensitive to low batteries. Then I'd drive through a tank of gas after resetting the codes and see if it just goes away. I might chance seafoam cleaner to gas tank also.

[UNH70SS]

I got the car back from the dealer the other day. The write up says there is a misfire in cylinder #4. I'm going to bring it to a mechanic a friend recommended next week.