$40-$80 to diagnose a problem really isn't bad at all. Remember, you're paying for labor, not for the job. The 2 hours that the mechanic spends diagnosing your problem is still two hours of his/her day, and that costs money. I've had some mechanics wave that fee if you let them fix the problem, but it's not a given. Just be lucky you don't have to deal with mechanics that want $85/hour at the minimum