Fuel flow

Have a afs 4500 with eis including fuel flow. Flew yesterday in below zero temps and fuel flow indication went to zero each time went to reduced power. No issue on ground. Never have had this issue in two yrs of flying but never flew at this temp. Anybody had any experience with fuel flow affected by low temps?

Water in fuel freezing?

Where is the fuel flow transducer located on the airframe?

On top of engine.. Will double check water