1999 Kia Sportage Trouble code P0300, P0301 & P0302

DTC P0300-P0304: RANDOM/MULTIPLE CYLINDER MISFIRE

Code will set if emissions relevant misfire rate exceeds 25 misfires per 1000 crankshaft revolutions. Code will set if catalyst damaging misfire every 200 crankshaft revolutions exceeds predetermined criteria based on load and RPM. Monitor runs continuously. Emissions relevant misfire is two trip fault. Catalyst damaging misfire is one trip fault and will cause Malfunction Indicator Light (MIL) to continuously blink.
Check for:
Vacuum leak in air intake system.
Crankshaft Position (CKP) sensor circuit malfunction.
CKP sensor malfunction.
Ignition circuit malfunction.
Faulty ignition coil or plug wire.
Spark plug malfunction.
Low compression due to blown head gasket, leaking valve or piston ring.
Low or high fuel pressure.
Fuel injector circuit malfunction.
Faulty fuel injector.