the when it on Moving Left it require a Lot of power to move it i think that the motor and the relay is Producing Back emf i have place diode for it and don't know the other concerned issue
Please - post some pics of your setup, your board, your schematic, your code...!
Are you saying it takes more power to move it to the left than to the right? If it is the same motor, that could be a mechanical issue?
Do you have decoupling caps on your Arduino board?
Are the relays identical to each other? How are they wired (once again - pics and a schematic could help us immensely)...?
If the motor is producing a lot of back EMF (or EMF in general - do you have caps across the terminals, and to the case of the motor?) - have you measured the noise using an oscilloscope (mainly between the line from the Arduino and the Arduino's ground) - to see if any back EMF is being injected in some manner that could cause a reset?
Does the system work correctly when "toggled" by hand - that is, when applying 5 volts/ground simulated HIGH/LOW to the transistors that control the relays (just like the Arduino would)? Have you tried using an optocoupler (well, probably two in your case - one for each relay) to completely isolate (both signal and ground) the Arduino from the motor controller?