Possible AFM issue

[cmich2015]

Picked up a 2008 Silverado LT 5.3L with 200k miles roughly a week ago. Im having an issue with it sputtering/misfiring both at Idle and crusing speed right around 1500-1800 RPM. I havent had it long enough to notice oil consumption. Has Check engine light on but code reads P0449 for the Evap System, Im getting about 12mpg which can partially be contributed to my 285 Mud tires as well as an evap issue.

Are there any Definitive ways to confirm if its AFM or not?

[adamhoude88]

With out a good scanner your dead in the water. But yes they are common for oil consumption in the early years like yours. My 08 and 12 both had oil consumption problems the dealers then did some things on warranty. The AFM is controlled by oil so it's often related to sputtering. I would think the evap code would not be related

 

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[MHA1406]

I had an 08 Silverado with the 5.3/afm. When mine went out I had a loud ticking and check engine/service stability sys light