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FIXITMAN
FIXITMAN, Master Technician
Category: Buick
Satisfied Customers: 17144
Experience:  ASE MASTER CERTIFIED, AA DEGREE AUTO/DIESEL TECH
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My 2007 lucerne cxs started misfiring so I changed all the

Customer Question

My 2007 lucerne cxs started misfiring so I changed all the spark plugs and put in a fuel cleaner by Chevron. Now it is misfiring and the service stabilitrak/service traction control warning comes on the information panel, and my check engine light flashes. It also surges forward when driving. My local mechanic cannot figure it out. He replaced another coil and replaced an already brand new spark plug with another new one. Please, help!
Submitted: 1 year ago.
Category: Buick
Expert:  FIXITMAN replied 1 year ago.

Hello, my name is***** for the question. Did your mechanic happen to give you the codes from the computer?

Customer: replied 1 year ago.
He hasn't. He just said he checked something that read engine coil 4, and spark plug 5 . The check engine light also doesn't read the misfire out register it
Expert:  FIXITMAN replied 1 year ago.

Thank you. Even though it was not throwing a misfire code can you tell me when this misfire was occurring? At all speeds?

Customer: replied 1 year ago.
It happens at idle, in park, when I am going about 5 miles per hour, and between 55 and 60 mph
Customer: replied 1 year ago.
Or at least I think it does. It shakes a bit, and surges forward like it is trying to go but has trouble.
Expert:  FIXITMAN replied 1 year ago.

Thank you. I have one last question. Does it do this every time you drive it or does it drive fine some of the time?

Customer: replied 1 year ago.
It started out faint, every few times I drove it would kick. After a while it got a bit worse so I put the fuel injector cleaner in and changed the spark plugs. After that is when the check engine light started flashing and the service stabilitrak/service reaction control reads on my information panel
Customer: replied 1 year ago.
Traction not reaction
Customer: replied 1 year ago.
that is always constant
Expert:  FIXITMAN replied 1 year ago.

Thank you. I am really curious to know what the codes are if you can possibly get those. As for the issue, it really sounds like it may have low fuel pressure or that the air flow meter may be failing. I typically recommend cleaning the air flow meter first to see if it changes.

Customer: replied 1 year ago.
I'll definitely get you the codes when he is open.
Expert:  FIXITMAN replied 1 year ago.

Thank you. I will look for your response later.

Customer: replied 1 year ago.
Okay. My mechanic said the code is reading P0300 random cylinder misfire from the computer. All spark plugs are replaced, and the bad cylinder was replaced. But still throwing the code and doing all I've listed above
Expert:  FIXITMAN replied 1 year ago.

Thank you for getting that information. More than likely this is either due to low fuel pressure or a failing air flow sensor. I would clean the air flow sensor first to see if it helps. The fuel pressure must be above 55 psi. If it is not then the fuel pump needs to be replaced.

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