03 f150 idles fine no check engine lite. Put in reverse or drive & dies instantly. No previous trouble at all. Any help apprecieated

 

Sounds like the torque converter is staying locked up.

 

I agree with Fireball...the torque converter has a solenoid that locks it in for overdrive.This effectively directly connects the engine to the rear axle.If this solenoid is stuck,it will indeed do what you describe.Concerning how to fix it,I suspect that either the solenoid needs to be changed out,or the torque converter is internally damaged,and needs replacing.