random misfire????

[mason313]

Well the missfire started about a week ago on the freeway when I was trying to pass someone. Was fine the rest of the time until the other day it would missfire anytime I got to around 3k rpms. Now its shaking real bad at idle. So I went and checked the codes I had a random missfire. Didnt pin point a certain cylinder. The plugs and wires where dont in the summer but I went ahead and changed the wires no change. I started getting a 02 sensir code for bank 2 so I replaced the 02 sensor. Now its reading a maf code I cleaned the maf with no change so I tried one off my buddys truck still no change??? Im also getting a bad squealing noise from the drivers side of the motor. I read something about a missfire and squealing sound could be 1. Worn camshaft lobe and/or lifter roller2. A sticking valve3. Valve leakage4. A broken valve spring5. A collapsed AFM (Active Fuel Management) lifter.

Any help would be great guys thanks

This is on my 04 Denali xl

 

[07tahoerida]

A collapsed AFM lifter is the problem just fixed mine, seems like the AFM lifters get stuck and wont re-open causing it to missfire. this was on my 07 tahoe