Misfire diagnostic trouble codes in your 1997 Ford Explorer are the P030x codes. P0300 indicates the misfire detection monitor detected a random misfire. If the MDM detects a misfire in a specific cylinder, the cylinder number is the last digit in the DTC -- P0301 for cylinder No. 1, P0302 for cylinder No. 2, and so on through P0306 for the 4.0-liter V-6 engine or P0308 for the 5.0-liter V-8.
The MDM defines a misfire as the absence of combustion. It makes no determination as to why. Simply running out of gas can log misfire codes. If your Explorer is running okay, reset the DTCs -- by using a scan tool or by disconnecting the negative battery cable for at least five minutes -- and then see if any of the codes return. If the "Check Engine" light is blinking at a steady rate and the truck is running poorly, the misfire condition is severe enough that you can cause damage to the catalyst if you continue to drive it.
