What causes P0302 on a GMC Sierra 1500?

Common causes of P0302 on GMC Sierra 1500: Failed or worn spark plug on cylinder 2; Bad ignition coil on cylinder 2 (coil-on-plug design on all modern GM engines); AFM/DFM lifter failure on cylinder 2 (5.3L and 6.2L V8s); Fuel injector failure or clogging on cylinder 2; Low compression from burned valve or head gasket leak (1.5T known issue).

P0302

P0302 GMC Sierra 1500

Q: How much does it cost to fix P0302 on a GMC Sierra 1500?

Fixes for P0302 on GMC Sierra 1500 include: Replace spark plug on cylinder 2 with ACDelco 41-162 (Iridium) or equivalent, Replace ignition coil on cylinder 2 with ACDelco D513A or equivalent, If AFM/DFM lifter failure, replace lifters and consider AFM delete kit, Clean or replace fuel injector on cylinder 2, Perform compression test to rule out mechanical failure.

Cylinder 2 Misfire Detected · Powertrain Code · High · Repair: Moderate

What is P0302?

Misfire detected in cylinder 2. Typically caused by a worn spark plug, bad ignition coil, faulty fuel injector, or low compression in that cylinder.

When the GMC Sierra 1500 triggers code P0302 (cylinder 2 misfire detected), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the GMC Sierra 1500.

This repair is rated moderate, meaning some experience and specialty tools required.

Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your GMC Sierra 1500.

Common Causes on GMC Sierra 1500

Failed or worn spark plug on cylinder 2
Bad ignition coil on cylinder 2 (coil-on-plug design on all modern GM engines)
AFM/DFM lifter failure on cylinder 2 (5.3L and 6.2L V8s)
Fuel injector failure or clogging on cylinder 2
Low compression from burned valve or head gasket leak (1.5T known issue)

Symptoms

Check Engine Light on (flashing if severe)
Rough idle with noticeable vibration
Loss of power
Misfiring felt during acceleration
Possible fuel smell from unburned fuel

Recommended Fixes

Replace spark plug on cylinder 2 with ACDelco 41-162 (Iridium) or equivalent

Replace ignition coil on cylinder 2 with ACDelco D513A or equivalent

If AFM/DFM lifter failure, replace lifters and consider AFM delete kit

Clean or replace fuel injector on cylinder 2

Perform compression test to rule out mechanical failure

Notes for GMC Sierra 1500

On GM V8s with AFM/DFM, single-cylinder misfires on cylinders 1, 4, 6, or 7 (AFM cylinders) strongly suggest lifter failure — cylinder 2 is less commonly an AFM lifter issue.

P0302 GMC Sierra 1500

What is P0302?

Common Causes on GMC Sierra 1500

Symptoms

Notes for GMC Sierra 1500

Check GMC Sierra 1500 Specs