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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 29396
Experience:  GM Grand Master Technician 2007. 14 years experience.
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GM yukon xl have a 5.3 liter engine misfire cylinder 7 and

Resolved Question:

have a 5.3 liter engine misfire cylinder 7 and open circuit cylinder 7 engine defaults to v8 mode switched coil wire with cylinder one but still have misfire in 7 engine jight stays on and traction control light comes on what causing this problem this time there is no lifter knock and occasionally on start up, engine will run on all eight cylniders but after 10 minutes or so it will start to misfire seems to be a common problem with this engine especially when engine has heavier mileage on it what is the problem?
Submitted: 5 years ago.
Category: GM
Expert:  GM Tech (Cam) replied 5 years ago.
Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.

These are known for issues with the special lifters for the cylinders that cut out. Those cylinders are 1 4 6 and 7 and the fix is to replace those lifters.
IF you are under the 100000 miles then this should be under the power train warranty.
Customer: replied 5 years ago.
this is the second engine in this vehicle warenty is done there is no lifter knock but your saying lifter could be bad any way had same problem with other engine replaced lifters 3 times problem always came back eventually just replaced engine
Expert:  GM Tech (Cam) replied 5 years ago.
These will not give lifter knock.
What is your mileage?
These lifters unlock to allow the cam to move the body but not the valve so spring pressure keeps it all tight causing no noise.
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