2008 Silverado 1500, LMG 5.3L/4L60E, 372,xxx miles.
Long time customer, He's a driller in the West Texas oil patch so he really racks up the miles.
I turned off the AFM in the ECM years ago when it had a little over 100,000 miles.
The intake lifter on #4 decided it was time to act out by collapsing intermittently, Made quite a loud snapping noise followed by a misfire on #4. The snapping noise is from the lifter collapsing on the nose of it's cam lobe instead of on the base circle.
A leaky AFM Solenoid can cause this, So I installed a Non-AFM valley cover first. Think it actually got worse/more frequent
Gave him some options.....6.0L swap, Rebuild, New engine, AFM Delete. He wanted cheap as possible without cutting corners.
AFM delete it is......
*Used LQ4/LQ9 camshaft.
*GM Performance LS7 lifters 12499225, I usually use GM Performance "Bowite" lifters.
*Summit Racing lifter trays.
*GM cam gear.
*GM LS2 chain damper.
*GM timing chain
*GM head gaskets & bolts
*Fel-Pro valve cover, valley cover, & timing cover set.
*Recently had a Mahle oil pan gasket installed & I was able to save it
*Recently had an oil change so I drained it into clean jug, I'll run it during the test drive....Then spill it for some fresh oil.
*Didn't run any parts through my spray cabinet, Heating 80 gallons of water from 60° to 170° isn't free.
The hardened surface on one of the lobes was starting flack, I didn't keep track of the lifter order upon disassembly & couldn't identify the lifter from that lobe as there was no discernable damage to any of the lifter rollers.