01 ford focus p0303

Question

Change plugs wires coil valves head and intake gasket hold compression at 125 psi drives good still throwing p0303

Answer 1

P0303 Misfire number 3 cylinder

P0720 Insufficent input from OSS sensor (output speed sensor)

Check the fuel injector for proper firing. And check power to the fuel injector harness and injector signal from the injector harness, Compression test are great,but still yet a leak down test does better job.