P0300 common causes

Question

This code comes and goes. In other words the CEL will come on for a day, then goes out on its own. When the light comes on is always at cruise speed. 40- 75 mph. And I do feel the misfire. Never misfires at idle, or under 40mph. What are the most common causes for this p0300 with the situation I've described?

Answer 1

P0300 Random misfire

The most common cause is the distributor cap

Here the distributor cap

 From the inside of the distributor cap the secondary can touch creating a misfire condition

 If this misfire is from the distributor cap and is allowed to go on for to long, you can blow apart the throttle body cover.