2005 Pontiac P0305: What It Means & Is It Safe to Drive?
P0305 on the 2005 Pontiac: Cylinder 5 Misfire Detected. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
What this code means
Misfire on cylinder 5—present on V6, V8, and inline-5 engines only. On V6 engines, cylinder 5 is sometimes harder to access; factor labor into repair estimates.
Common causes on the 2005 Pontiac
- Fouled spark plug
- Failed ignition coil
- Leaking or clogged injector
- Low compression from valve or ring wear
Symptoms
- Check Engine Light
- Engine shaking or rough idle
- Power loss under acceleration
Typical fixes
- Replace spark plug and coil on cylinder 5
- Test and replace injector if needed
- Compression and leak-down test
Repair cost range
For a 2005 Pontiac, repairs for P0305 typically fall between $150 and $1000, depending on the root cause and labor rates in your area.
Known issues on Pontiac
Pontiac G8 and GTO LS2 V8 P0305 is uncommon on these extremely durable engines. When it occurs, a failed COP coil or fouled spark plug is the typical cause. On the 3.8L supercharged Grand Prix, P0305 is more common from coil boot cracking due to heat near the supercharger.
Most commonly affected models