P0306 on a Chevrolet Silverado 1500
P0306 means cylinder 6 Misfire Detected. On the Silverado 1500, a few causes come up far more than others.
What P0306 usually means on a Silverado 1500
P0306 isolates the misfire to cylinder 6, another of the AFM-deactivating cylinders on the 5.3L V8. When cylinder 6 misfires hard and the engine ticks, a collapsed AFM lifter is high on the list, more so than a coil or plug. On engines without AFM, or where there is no tick, the ordinary single-cylinder ignition and fuel suspects apply. Knowing that cylinder 6 is an AFM cylinder shapes the whole diagnostic approach on these trucks.
Most common causes on the Silverado 1500
- Collapsed AFM lifter on cylinder 6 (5.3L)
Cylinder 6 deactivates under AFM, so a hard misfire there with a tick points to a failed lifter, a mechanical failure inside the engine.
- Failed coil or worn plug on cylinder 6
The routine single-cylinder misfire cause; swap-test the coil and inspect the plug before assuming anything internal.
- Oil-fouled plug from AFM oil consumption
An oil-consuming 5.3L can foul cylinder 6's plug, producing a misfire that recurs until the oil issue is dealt with.
- Injector or compression fault on cylinder 6
A leaking injector or low compression, possibly from a lifter-damaged cam lobe, causes a misfire ignition parts will not cure; a compression test confirms.
What P0306 costs to fix on a Silverado 1500
Ignition parts for cylinder 6 are inexpensive; an AFM lifter failure is a teardown-level, four-figure repair that should include a cam lobe inspection for that cylinder. As with the other AFM cylinders, the money-saving move is confirming lifter versus ignition before opening the engine.
Fixing it
Listen for a tick and check compression on cylinder 6 before buying parts. If ignition components are fine and the cylinder is an AFM cylinder with a tick, plan for lifter work and inspect the camshaft lobe.
For the full step-by-step diagnosis order (any vehicle), see the main P0306 guide.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
Other codes on the Chevrolet Silverado 1500
Chevrolet Silverado 1500 problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0306 behavior is covered on the main P0306 page. Confirm with a scan tool before buying parts.
P0306 on your Silverado 1500?
Every problem becomes a Case. Tell Redline what your Silverado 1500 is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.