P0308: Cylinder 8 Misfire Detected
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Short careful trips only - catalytic converter damage accumulates quickly.
Symptoms
- Flashing check engine light
- Heavy vibration at idle
- Ticking or knocking under load
Likely causes, most common first
- Coil or plug on cylinder 8
- Injector fault
- Collapsed lifter or deactivation fault
- Low compression
Read P0308 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0308 is cylinder 8 - the last cylinder of a V8, and the one most often reported on engines with cylinder deactivation. On those designs cylinder 8 is among the cylinders switched off at cruise, and a lifter that fails to reactivate produces a persistent misfire that ignition parts will never cure.
The distinction matters financially: a coil is a hundred-dollar repair, a collapsed lifter is a four-figure one. A mechanical tick that changes with engine load, or a misfire that appears only once the engine is warm and cruising, points at the lifter rather than the spark.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0308
“Vehicle lost power, debris in cylinder from internal damage, crank case leaking air, oil leaking into cylinder, P0300, P0308, and P050D”2021 Chevrolet Suburban · Jul 2024
“I brought in vehicle for check engine light is on for p0300 / p0308 had misfire tech removed engine valve cover and determine no movement in valve train components tech determine valve train failure lifters possible camshaft we would need to remove the cylinder head and replace valve train lifters.”2021 Chevrolet Silverado 1500 · Feb 2024
“While driving with the roads in a wet condition, for various lengths of time, and in different maneuvers, the service engine light will start flashing and the vehicle will begin to lose power. After a few minutes, the service engine light will go solid and the traction control light will illuminate. The vehicle loses more power. On braking, just before the vehicle comes to a complete stop, there is a clunk in the transmission and the vehicle lurches. This has occurred 6 times in the last 14 months. Upon investigation, trouble code p0308 shows in the obd tool. The issue could not be reproduce by the dealership so there has not been any resolution, just thoughts.”2018 GMC Sierra 1500 · Feb 2021 · 33,000 mi
Show 2 more owner reports
“After purchase, I got a continuous p0308, cylinder 8 misfire. Problem is that cylinder 4 has low/no compression, dragging down cylinder 8 as well.”2013 Ford F-150 · Dec 2018 · 82,000 mi
“Loss of power when getting on freeway. Engine chugs, rough idle, no power to merge with traffic on freeway. Check engine light came on. Checked codes and found p0308 and p2099. Changed all 8 spark plugs, plugs 4, 6, 8, 3, 5, and 7 show sings of setting in water. Found out dodge has two service bulletins to keep this from occurring, sb 18-006-05 rev a and 18-024-06. Do we need crashes on the freeway before we can force dodge to fix this on all 2004 and 2005 dodge durango with the 4.7 l engine. *tr”2005 Dodge Durango · Dec 2009 · 51,308 mi
Cars that report P0308 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0308?
Short careful trips only - catalytic converter damage accumulates quickly.
How much does it cost to fix P0308?
Typical US repair costs range from $20 for the simplest fix (spark plug) to $4,000 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P0308. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.