No, your gas mileage will be fine. Maybe power would suffer a little, but I sort of doubt that it would be really noticeable.
If you are not reading anything between pins 1 & 2 on the sensor plug, then it sounds like it is broken.
I am not sure if I followed the correct route while reading it but I had no number when I unplugged it and read from pin 1 ad 2..
about 5 or 6 years ago I had another m42 and it was pulling really fantastic I mean I was feeling every torgue.. and we install a LPG system on it and the first time we run it with LPG the cur didnt run smooth and it run well untill 2000 rpm and really slowed down until 3000 rpm (almost no acceleration) then was very good after 3000 rpm.. at that time I had so little knowledge about m42 and later we resetted ecu almost 15-20 times until it runs normal.. but rememnber it was normal not perfect (just like my car now) then I had a stomp test and saw the camshaft position sensor code on ecu on my previous car... we deleted the code and got no more code again.. but that car never pulled the way it did before LPG and that camsahft position sensor code.. then I reinstalled the LPG and went on with normal oil/petrol.. but it was never like before..
Now, I checked everything about car but this is the last thing I am suspicious about.. I am suspicious because of my previous experience..
Now I need your comments

this is quoted from:
http://www.autozone.com1.The static hall sensors are used on this sensor so that the camshaft positions are recognized once ignition is on and even before the engine is started.
2.There are four functions of the intake camshaft position sensor:
Cylinder bank detection for preliminary injection
Synchronization
Engine speed sensor (if crankshaft speed sensor fails)
Position control of the intake cam (VANOS)
3.The exhaust camshaft sensor is used for position control of the exhaust camshaft as part of the VANOS (variable camshaft control) system.
4.
If these sensors fail, there will be no substitute values and the system will operate in the failsafe mode with no VANOS adjustment. The engine will still operate, but a significant reduction torque reduction will be quite noticeable.