Re: Just bought a Taurus
The camshaft sensor is a $30 magnet in plastic that sits over the camshaft synchronizer. Often the adhesive on the magnet gives way and lets the magnet fall into the synchronizer, bending it. That's a reasonable price to put in a new camshaft synchronizer, but he should have noticed it was bent in the first place. Most likely it tore up your new sensor.
I know this because it happened to me, but I managed to straighten my old synchronizer just enough so that it only wears out a sensor every few years. At that rate the car will be in the bone yard before I get to $250.
Don't worry about the timing chain it will likely last longer than the car. That's why they put them in!
So if you're spoiling for a fight, I'd go back to this mechanic and say, go ahead and replace the synchronizer, but if I need a new sensor its on you buddy, for either not paying attention, or deliberately trying to cheat me.
After that I would never go back again.