Honest, good mechanic in Cleveland area to diagnose my car and give me options

I'm not from Ohio, and I need to drive about 500 miles in a few weeks (back home, permanently), but my car is a mess. I don't think it will make it. It gets around, but the check engine light is on, and it drives pretty rough most of the time. Looks to be a spark plug issue, but could be worse.

What I need is pretty simple, a good mechanic to diagnose my car honestly, give a fair assessment of the cost, and then let me make a decision about what I do with the car. Obviously I expect to pay the guy to tell me what's wrong with it.