04 Ga Stalling

I have a GA that is stalling. Works fine up until it is warm. The Check Engine light is on. Once warm and once I hit the breaks and let go of the gas peddle and the engine starts to stall, the dash goes dim along with the headlights, then the car completely stalls. I am able to turn the car back on but this happens again and again everytime I let go of the gas peddle and the RPMs get below 1500. I took the car to an AutoZone and had the codes checked (I am not sure what that code was) which indicated that the car required a change of a spark plug or 02 sensor. I got the sensor changed and the car worked fine for some time (no stalling) but the Check Engine light was still on. Took the car to an AutoZone today and had P0171. Can anyone help me determine the problem or give me any suggestions?
:popcorn:

The P0171 is system to lean.

Which engine does your GA have ?

Have you tried changing the fuel filter ?
Have you replaced the plug & wires or are they still factory ?

Thanks for replying,

It has a 3.4L motor (SE model). I have not tried to change the fuel filter, but will try that.

I think that the cables and the plugs are still the factory installed ones.

I will post the results as soon as available - thanks a lot:)