P0301Cylinder 1 Misfire Detected

What it means

The same detection as P0300 — the crankshaft momentarily slows where a power pulse should be — but isolated to cylinder 1. A single-cylinder misfire is good news diagnostically: everything that could cause it lives in or feeds one cylinder, so the search is short.

Is it safe to drive?

Caution

The same rule as every misfire: a steady light and a mild stumble means drive gently and fix it within days. A flashing light means unburned fuel is overheating the catalytic converter — ease off and stop as soon as it's practical. A dead cylinder also washes its cylinder wall with raw fuel, so "it still drives" shouldn't buy it many miles.

Common causes

Most likely first.

• A worn or fouled spark plug in cylinder 1
• That cylinder's ignition coil, or its plug wire on older cars
• A clogged or dead fuel injector on cylinder 1
• A vacuum leak at that cylinder's intake runner or gasket
• Low compression in that cylinder — a burnt valve, worn rings, or head gasket

What the live data shows

The per-cylinder misfire counters make this code satisfying to chase: cylinder 1's count climbing while the others sit at zero confirms it's real and localized. Watch idle RPM dip rhythmically, and read the freeze-frame — a misfire only under load points at spark breaking down (coil or plug); at idle, at vacuum or the injector.

A scanner that reads all 139 standard sensors shows you these readings live. ScanMyCar charts them as you drive, keeps the freeze-frame stored with the code, and pulls codes from every module — free, with any cheap Bluetooth adapter.

Typical fixes

Cheapest first, where honesty allows.

• Replace the spark plug — and read it; its condition is a diagnosis in itself
• Swap coil 1 with another cylinder; if the misfire follows, replace the coil
• Test or swap-test injector 1 the same way, where accessible
• Compression-test cylinder 1 if spark and fuel check out