NO, I did not put diesel in my tank.
I recently started to drive my ranger after it sat for about a year. That's when my dad decided to give it to me. The truck did burn a bit of oil, that I kept refilling at about 1.5 quarts a week. I did have plans to have a friend of mine try to help me fix the valve cover gasket in a few weeks when we both have time, which I think was bad.
I was driving my ranger to school yesterday, on a short stretch of highway, when my truck started to slow down even while the gas was pressed. I gave it a little more gas to compensate for the small hill I was driving up. The truck kept slowing down and the check engine light started to flash. I was starting to pull over and the light stopped flashing. I was almost to school so I drove it about the 1/4 mile left to the parking lot of the school and not on the side of the highway.
Now when my truck is idling, it sounds like a diesel engine. The engine shakes a lot when idling. I'm sure there is something knocking in the engine from the way it sounds.

Does anybody have any insight as to what this could be? I need to figure out if I should try to fix this truck or... what my options could be at this point.

Thanks

Newt

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02 ranger, 2.3 4cylinder, 2wd, single cab, 135000+ mi.
i do search previous posts/threads, so if im asking, i cant find it