Ignition and misfires code
P0305: Cylinder 5 misfire
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $30 | $120 |
| Labor: 0.4 to 1.2 hours × $125 to $175 an hour | $50 | $210 |
| Fees: shop supplies, disposal, diagnostics | $0 | $15 |
| Total, rounded | $80 | $350 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in Boston, $31.54 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, ignition coil replacement (one coil). Which repair your car needs depends on a proper diagnosis.
Cylinder 5 is the one skipping its burn. The computer spotted it from small slowdowns in the crankshaft that line up with cylinder 5's turn to fire. This code only appears on engines with five or more cylinders, usually a V6, V8 or inline five or six.
- Safe to drive?
- Short trips only
- Most common cause
- Worn spark plug in cylinder 5
A steady light means short drives are okay; a flashing light means stop, because raw fuel can ruin the catalytic converter.
What you may notice
- Shaking, worse at idle
- Flashing check-engine light
- Hesitation when accelerating
- Often a stronger fuel smell
Common causes, most likely first
- Worn spark plug in cylinder 5
- Failing ignition coil on cylinder 5
- Clogged or weak fuel injector for that cylinder
- Vacuum leak near that cylinder
- Low compression from a valve or ring problem
Check this first
Find cylinder 5 on your engine layout, then ask for its coil to be swapped with a neighbor's and the code cleared. If the miss follows the coil, replace that coil. If it stays at cylinder 5, the plug or injector is next.
Other repairs that sometimes fix P0305
| Repair | Typical range, Boston |
|---|---|
| Spark plug replacement | $95 to $580 |
| Fuel injector replacement (one injector) | $180 to $910 |
| Vacuum leak repair | $100 to $530 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Massachusetts rules require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
P0305 questions
How do I know which cylinder is number 5?
The numbering depends on the engine, so check a diagram for your make and model. On many V6 engines cylinder 5 sits on the opposite bank from cylinder 1, which helps a shop find it quickly.
Should I replace the plug or the coil?
If the plug is old, change it first, since it is a low-cost part. If the plug looks fine or the miss follows the coil, replace the coil. The swap test tells you which without guessing.
Can I keep driving with this code?
A short, gentle drive with a steady light is usually okay. Skip towing and steep hills, and stop if it flashes, since a strong misfire can overheat the catalytic converter quickly.
How much does it cost to fix P0305?
The most common fix, ignition coil replacement (one coil), has a typical range of $80 to $350 in Boston. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
Related codes
More ignition and misfires codes
Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.