Why is my Pontiac G8 GT ticking and misfiring?

Short answer: On the G8 GT's 6.0L V8, a new loud tick with a misfire is often a failed AFM lifter. AFM (Active Fuel Management) shuts off four cylinders to save fuel using special lifters (the parts that ride on the camshaft and open the valves). When one collapses or breaks, that cylinder misfires and the engine ticks. Owners call it the most common G8 problem.

Symptom: A ticking noise that gets louder, a check engine light, a misfire on one cylinder, and rough running.

What to check first

1. Read the codes. A misfire code on a single cylinder with a tick is a strong hint.
2. Listen at the valve covers to find which side the tick is on.
3. Check the oil level. Low oil makes lifter problems worse.
4. Ask a GM dealer about the AFM lifter bulletin and whether any coverage applies.

Likely causes

1. Failed AFM lifter. Owners report lifters collapsing or even breaking in two.
2. Bent pushrod or worn camshaft lobe. Can follow a lifter failure.
3. Ignition coil or plug. Rule these out on a misfire without a tick.

What it usually costs

The threads didn't list prices. Some owners replace all the AFM lifters; others install an AFM delete kit (and need a computer tune). Get a written quote.

Is it safe to keep driving?

Not for long. A failed lifter can damage the camshaft and more. If it's ticking loudly and misfiring, drive it gently straight to a shop. Verify with a mechanic.

DIY or shop?

Shop for most owners. Lifter replacement means removing the heads on this engine.

Recalls, bulletins and complaints in plain words

• Recalls: NHTSA lists no recall for the engine on the Pontiac G8 for these model years (checked 2026-10-23). Other recalls may exist for your car, so check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• Service bulletin: GM bulletin 15-06-01-002M covers engine tick and misfire from AFM valve lifters on V8s. See the GM bulletin.
• NHTSA complaints: 55 keyword-matched complaints for Pontiac G8 2008–2009 (of 215 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-23; keywords: lifter, AFM, tick, misfire, cylinder deactivation, camshaft). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In g8 common problems? on LS1Tech, G8 owners said AFM lifter failures and lower control arms are the most common problems, followed by strut mounts, warped brakes, driveshaft vibration and fast rear tire wear.
• In Your AFM lifter problem?? on LS1Tech, members described the loud tick and misfire codes from failed AFM lifters on Gen IV V8s, and one posted an AFM lifter he found broken in two pieces. (The thread was started by a parts vendor selling AFM delete kits.)

Quick tip

If you hear a new tick and get a misfire code, stop and find out. Catching a lifter before it chews up the cam can be the difference between a lifter job and a cam job.

Vehicle focus: 2008–2009 Pontiac G8 GT with the 6.0L L76 V8 and AFM. The G8 GXP (LS3) and V6 models do not have AFM lifters.

Safety / mechanic note

A failed lifter can damage the camshaft and engine. Verify with a mechanic.