Where is the cam sensor located in a 98 Mazda 626?What does the repair cost?

The cam sensor is in the distributor. I don't currently have a parts estimator but I think the distributor is about $350 and labor should be 1 hour. Easy job. You better diagnose the problem before trying to get lucky and buying a distributor. Generally if you have fuel and there's no spark, but power and ground at the distributor are good, it's failed. A failed cam sensor in the distributor in one of these cars is a common problem. Here's a directory link for you: http://repairpal.com/mazda-repair-in-shawnee-kansas