Low power at start slowly picks up when u play with rpms

My 3.1 motor is messing with me. It has very low/bogging out when u take off normally and it will slooowly pick up speed as long as keep it under 3000 RPMS. First it threw a code for egr insufficient flow. Took off egr valve cleaned it and the passageway really no difference just light when off then after like 5 hours or so it threw a code for bad coil replaced the coil it said runs slightly better meaning it picks up a little better but not what it should. If u step too hard on the gas it it just bogs out and doesn't accelerate so u gotta watch the RPMS to not strain the motor n trans. The car is new to me only had it a month. Has new irdium plugs and wires on it. New air filter. Also due to the gas gage not working i have ran it out of gas three times now. It doesn't seem like it's getting the right amount of miles for a full tank. This time it only got 246 miles for a full tank. 18.5 gallons. Fuel filter???