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BOBBYSS
BOBBYSS, Master Technician
Category: Chevy
Satisfied Customers: 17142
Experience:  ASE MASTER CERTIFIED, AA DEGREE AUTO/DIESEL TECH
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2014 Tahoe engine misfire/stumble when im sitting at stop

Customer Question

2014 Tahoe engine misfire/stumble when im sitting at stop light with foot on brake
Submitted: 1 year ago.
Category: Chevy
Expert:  BOBBYSS replied 1 year ago.

Hello, my name is***** you for the question. Can you tell me if the check engine light is coming on? How many miles are on it? Does it do this every time you drive it?

Customer: replied 1 year ago.
44000 miles it is at the dealer now spark plugs wires are good they did a leak down test past there is no check engine light on and that's the problem they are having because they cannot pull a code the technician verified the misfire / engine stumble
Customer: replied 1 year ago.
after its warmed up it happens all the time.
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  BOBBYSS replied 1 year ago.

Thanks for the response. Most of the time this is caused by the timing solenoid pack. It is prone to failure especially if the oil is somewhat dirty. They would need to tear down the top of the engine to verify this. Most of the time if it is not replicated GM needs to get involved to approve this.

Customer: replied 1 year ago.
The oil is not dirty it has been maintained and changed every 5000 miles I don't understand what you are talking about the solenoid pack the truck has a slight shake to it went its idling like at a stoplight
Expert:  BOBBYSS replied 1 year ago.

The solenoid pack is what changes the valve timing inside of the engine to help with efficiency and economy. If there is evena slight amount of oil bypassing the solenoids then it can cause a change in valve timing when it is not supposed to which causes it to run like this. The only other thing I have found is either dirty injectors, which is not really common or a programming issue in the computer. I would typically reflash the computer and clean the injectors first to see if it helps.

Customer: replied 1 year ago.
tech is thinking a coil pack on #6 cylinder that might be at fault. he is supposed to swap one out with another one from a truck on gm lot
Expert:  BOBBYSS replied 1 year ago.

That is possible, but typically that would cause a misfire code just for that cylinder.

Customer: replied 1 year ago.
I just bought this truck it's been in the shop 3 times for same thing. The last technician drove it over the weekend and validated my concern But nothing else has been done I don't know what's going on up there like I said they did the fuel system flush leak down test check plugs and wires and now their stock they said they were waiting for it to show up on computer to send to technical service support I'm frustrated
Customer: replied 1 year ago.
Is there a TSB service bulletin for this
Expert:  BOBBYSS replied 1 year ago.

There is a bulletin for the AFM system, which is the system I am talking about. I would ask them if they have checked this out. I do not have access to the bulletin itself at the moment but I can get you the bulletin number.

Customer: replied 1 year ago.
That will be great and you say this will cause Idling problems
Expert:  BOBBYSS replied 1 year ago.

It is PIP4568R. That should reference that bulletin.

Customer: replied 1 year ago.
PIP4568R can not find anything on that code
Expert:  BOBBYSS replied 1 year ago.

This is a technical bulletin that dealers get from the manufacturer for common issues. The dealer can print it out for you. They should know exactly what I am talking about with this. I can send it over later also if you need it.

Customer: replied 1 year ago.
please. just spent 40000.00
on this truck and for 20 days I feel as I am getting the run around. Thanks so much
Expert:  BOBBYSS replied 1 year ago.

My normal system is down, but this is what I have right now. Keep in mind the ticking noise and check engine light does not always occur with this when it is subtle.

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