I have a 2008 Suburban and while driving home from NY my stabiltrak and traction control light came on. when I pulled over to investigate i noticed a miss at low RPM. now the engine idles just under 500. When I got home I investigated some causes on this site I also got some codes read I show p0442, p0449,p0455,p0301,and p0521. So I tried swapping coil pak with 1&3 cylinder still no good. I have no compression on number 1 cylinder. Drained oil and out a flush through it and fresh oil. I'm thinking #1 cylinder is stuck in the AFM mode. any ideas on direction to take?
Charlie

 

cz113 Welcome to the forum...
Sounds like one (or more) of the AFM lifters has failed... typically there has been damage to the cam shaft when the failure occurs, but you never know you might get lucky... I'd get the head pulled off and have the cam checked...
I am not sure what the process is that the dealer follows for repairs but I would suspect that replacement of all the AFM lifters(or all lifters) and the cam shaft is in order...

 

Thank You in2pro, I suspected that the lifter was stuck just not sure if it is the solenoid for that cylinder or the lifter itself. I will have to tear it down, I should be able to test the solenoids before I actually pull the head. I believe that is under the intake?

 

Intake you are correct, only need to remove the valve cover not the head...is see a set of lifters for the afm go for about $225 all 8.

 

pulled the intake off and the LOMA along with the valve cover. the first valve assy does not move at all when turning the engine over by hand. it looks like the head needs to come off to replace lifter.
Chaz

 

in2pro where did you find the set of lifters ,i'm coming up empty on my search and being told they need to be purchased through dealer.

 

Sounds like a lobe is wiped off the cam. I don't think you need to remove the head to replace the lifter tho.

 

I found them listed on Ebay....

 

Well found the culprit for my misfire problem, i put a photo in photo album call AFM Lifter on this site not sure how to post a photo in the thread. The small pins were stuck in on the lifter and it came out in two pieces, I freed them up but replaced the lifters in the affected head.
Chaz

 

Here's the culprit