Code number? Motor size? It would help with more info like services done etc.
Misfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (CKF) sensor which is attached to the crankshaft. If misfiring strong enough to damage the catalyst is detected, the MIL will blink during the time of its occurrence, and DTC P0300 and some of DTCs P0301 through P0304 will be stored. Then, after misfire has ceased, the MIL will come on. If misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTC P0300 and some of DTCs P0301 through P0304 will be stored.
NOTE: If some of the DTCs listed below are stored at the same time as a misfire DTC, troubleshoot those DTCs first, then troubleshoot the misfire DTC.
P0106, P1128, P1129: MAP sensor
P0171, P0172: Fuel metering
P0505: Idle Control System
P1336, P1337: CKF sensor
P1361, P1362: TDC sensor
P1381, P1382: CYP sensor
P1508: IAC valve
Fuel pump insufficient fuel pressure, amount of flow
Fuel line clogging, blockage, leakage
Fuel filter clogging
Fuel pressure regulator stuck open
Ignition coil wire open, leakage
Ignition control module malfunction
Valves carbon deposit
Fuel does not meet Owner's Manual spec, lack of fuel