Why Your Car Revves Erratically Over p0304 No Mechanic Will Ever License

Thu, 16 Apr 2026 21:45:16 +0000

Why Your Car Revves Erratically Over P0304—And Why No Mechanic Will Ever License It If your car suddenly starts revving erratically, particularly under Malfunction Code P0304, you’re not just dealing with a mechanical issue—you’re facing a frustrating challenge that goes beyond regular repairs. P0304, which indicates a “Cylinder 4 Misfire Detected,” can cause inconsistent engine performance, rough idling, rough idling, and a noticeable shudder or stumbling when accelerating. But here’s the catch: while you can fix the misfire and bring your engine back in line, you can’t get your vehicle properly licensed by a mechanic—and here’s why. ### What Causes P0304 (Cylinder 4 Misfire)? Before diving into licensing concerns, it helps to understand the root:
P0304 means cylinder 4 is misfiring—meaning the fuel-air mixture isn’t igniting properly. Common causes include:
- Worn spark plugs or faulty ignition coils in cylinder 4
- Vacuum leaks near cylinder 4
- Low fuel pressure affecting that cylinder
- Contaminated fuel or clogged fuel injectors
- Mechanical wear such as a damaged piston or compression loss