Hi
I have a 27mhz am car radio it does work but the range has reduced  to 50 meters.....the throttle and servo function is all normal within 50 m but then it goes crazy.......does some one have ny idea what could b wrong with it?

Are you reporting reduced range from what you were getting earlier? Then the first thing to do is check both antennae.

Yes previously range was basically line of sight.....i have checked both antenae.........could it b the crystals?

Extremely unlikely.

Try in a completely different location to eliminate the possibility of interference.

What type of antenna do you have on the TX? Not familiar with Car Txs!