My check engine light went on today, so i took it to autozone and they scanned it. it threw code p0300, and p0420. i know the 2nd code is related to my cat being broken lol, but for code p0300 it says random/multiple cylinder missfire. the guy working there recommended that i change out the plugs, so i'm about to do so. my ? is, is it necessary to remove that metal heat shield that is surrounding the spark plug boot wire, or can i leave it on and pull on the remaining exposed part of the rubber boot? thanks!
--Adam
--Adam