I'm new at this, so bare with me. I have a po300 code, multiple misfire. when i put it in 5th gear on the highway, the car vibrates and the check engine light comes on so it shakes. can anyone help me figure this out on how to solve the problem.

 

Go make some popcorn and search P0300 on this site you'll return tons of useful info.

You can go to advanced search and search P0300 with my user name. I've posted a bunch about it over the years

 

ok, thank you

 

https://www.evolutionm.net/forums/ec...0300-test.html