I have a 99 e320 with a po300 code

Question

99 Benz e320, 65k miles, idles rough, drives fine, code is po300, check enjine light flashes when driving

Answer 1

Hi there,

Usually the light flashing indicates an electrical misfire. If you have a rough idle, you should be able to unplug one coil at a time and see which one is causing the misfire. Unplug one, if the engine runs rougher, plug it back in and move to the next. Do this until you get to one that doesn't change the way the engine runs and go from there.