Tyler Moyer

getting po300 code for a random misfire on an evo 9. It's not the plugs or wires. Anyone know what else to look for and how to check for it? Also have a strange rattling on noise coming from the serpentine belt area but only at certain rpms. Any help?

barneyb

An hour ago I pulled the clutch disc out of mine and the disc rattles like a baby rattle. A couple of the springs are loose.

Just my opinion but if the ECU can't provide a P301-4 then it (the code) is probably garbage. The crank sensor is detecting some abnormal rotation of the crank but that can be caused by drivetrain issues.

SHIFTT IX MR

Only thing that solved it for me, was fixing all my grounds, and putting in a new battery

SHIFTT IX MR

let me guess, the code sometimes acts consistent, and sometimes doesn't? am i correct?

Tyler Moyer

so the code goes away and comes back again. The car is misfire under load but that's the only time it does it. If I drive completely normal and never get on it it won't misfire.

barneyb

The code is generated when the crank sensor does not detect consistent crank rotation - whatever causes that.