Originally Posted by cheshirecat

The engine moving to around 1100 rpm is completely normal when this code is thrown. It'll stay that way until the code is cleared.

This code really is sort of a mystery with no 100% fix out there short of a tune and auto-clear. IMO, it's just a result of leaner air than expected entering the engine. As long as it's just a 300 code and it doesn't specify a certain cylinder, I wouldn't give it much worry.

It is pretty annoying, though.