P0304 means cylinder 4 misfire detected. Cylinder 4 isn't firing properly. The usual suspects are the spark plug, ignition coil, or fuel injector for that cylind
Drive gently and get it diagnosed within days.
Cylinder 4 isn't firing properly. The usual suspects are the spark plug, ignition coil, or fuel injector for that cylinder.
Start here.
Swap-test with another cylinder to confirm.
Restricted fuel to cylinder 4.
Mechanical issue — compression test confirms.
Localized lean misfire.
Typically $100–$500
Single plug/coil typically $100–$300; injector work typically $150–$400. Estimates vary by vehicle. Costs are estimates and vary by vehicle, location, and shop.
Drive gently and get it checked within days — prolonged misfires kill catalytic converters.
Typically $100–$500. Single plug/coil typically $100–$300; injector work typically $150–$400. Estimates vary by vehicle.
Drive gently and get it diagnosed within days.
The most common cause is worn spark plug in cylinder 4. Start here.