My service engine soon light has came on for the 2nd time in 2 months. Both times I was passing a car on the highway, around 75mph, and then the light came on out of nowhere. The first time I went to autozone to get it checked by the computer and it said "random cylinder misfires" the guy didn't know anything about cars, he couldn't even tell what kind of truck I have, but he said the best thing to do was to
take it to a shop. I took it to the mechanic I normally go to and he said my spark plugs were too weak and to replace them. I replaced them and everything seemed fine, until today, I was passing a semi and the light came on again and i don't know what's causing it. Can anyone help?