Misfire code 303

Good evening,

303 is a misfire for number three cylinder.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Some possibilities.

1. Plug

2. Wire

3. Injector malfunction

4. Vacuum leak

5. Low compression

6. Valve train damage

7. Failed PCM from not signalling injector to fire.

I would start by checking compression.

https://www.2carpros.com/articles/how-to-test-engine-compression

Roy

303

P0303
Descriptor
Probable Causes
Evaporative Emission (EVAP) System
Evaporative Emission (EVAP) System Canister Purge Valve
Fuel Injector 3
Fuel Pressure Incorrect
Ignition System
Mechanical Engine Failure
Vehicle Running Out of Fuel