Hi guys, my 2002 pro5 has been flashing me the CEL off and on for 2 weeks.
When the light is flashing the power drops off to about half, as soon as it quits flashing- bang- ready to go again.
I've changed the plugs and wires, no change.
Code 300 means "random misfire"
I'm hunting for idea's...
I really don't know whether its spark or mixture related.
Any thoughts?
Pat

 

the exact same thing happened to my 02 mp5 and after 8 trips to the dealership and all kinds of things being replaced it ended up being my o2 sensors. acording to mazda USA those will make it "missfire" if there heated(whatever that means). hope that helps.