24/07/2026 8:38 am
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Silverado cylinder 6 misfire is being called an AFM lifter without a mechanical test
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A 2016 Silverado 5.3 has an intermittent P0306 and a light tick. Because cylinder 6 is part of the cylinder-deactivation system, a lifter has been suggested. Compression and running relative compression are even when the fault is absent, and moving the coil and plug does not move the misfire. The injector connector reacts to side pressure.
What would prove or disprove a valvetrain fault before removing the head?
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25/07/2026 8:31 am
Capture cylinder contribution, running compression and an in-cylinder or intake pulse comparison while the misfire is active. A collapsed lifter should change valve motion or cylinder pressure, not only the injector circuit. Scope injector current and control voltage at the same time; a dropout synchronized with the misfire directs the diagnosis away from the valvetrain.
Inspect terminal tension with the specified probe. Pattern failures are useful context, but the active event must show whether combustion was lost from fuel, spark or mechanical motion.
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26/07/2026 7:53 am
During the misfire, injector current on cylinder 6 vanished while the control command remained at the ECM. The connector terminal had a cracked crimp. After terminal replacement, current and contribution stayed even and the tick was traced to a loose heat shield, not a lifter.