Hi Scotty, I have a 2001 Ford Escort. Lately when I hit 40 mph the car starts to jerk and miss kind of violently. Lots of trouble accelerating. I have code P0171. And I have an obd 2 scanner that pulled TID $41 CID $11 and TID$41 CID$12. What can this mean? Help would be greatly appreciated. Thank you

it's running lean, try cleaning or changing the MAF sensor, and do check for vacuum leaks. Also pressure test the fuel pump to see if it's weak