I own a 2000 Ford Focus, and the engine light stays on, despite being maitenced for the cause 2 different times. I've spent nearly 700 trying to fix whatever issue is, I need this check engine light problem to be resolved due to smog. My mechanic thought the sensors were bad, so he replaced the oxygen sensor, the motor mounts, then transmission mounts, then spark plugs, then wires. After a while, he just told me there was nothing else he could do as the codes weren't adding up (cylinder misfire 4)
Right now, I really don't know what to do, any advice is appreciated thanks.