How do i fix my sudden loss of power while driving for about 45min.if the car is allowed to rest for about 5 min everything will be ok again

The first thing to do is replace the fuel filter. If the problem continues get the fuel pressure checked and if low replace fuel pump.
Check the fuel pressure with the engine revving and not just at idle.

This error code indicates that the vehicle is running very lean, a lean fuel intake means there is excess air getting in to the system. The on-board computer is unable to compensate affecting the fuel mixture, a common cause is a leaky vacuum leak.
you should find that your fuel usage is very high also.
If you take it to a garage and request a smoke intake test, they should run the test with the vehicle not running the smoke will find its way to the hole or faulty item.
For more information please take a look at some YouTube error codes. here is one example How to Diagnose OBD II Fault Codes P0171 and P0174 Leaking Intake and EGR...