2003 Dodge Neon

I made a Donation but did not get to ask question so here I go, car is losing power when going up hill, the more gas I give seems to decelerate pedal to the floor and it stutters reach top of hill and it is ok for a minute, also wants to die at stops. The code reader says P0016 showing as 2 different problems, when I scroll down the second says pending, ckp and cmp sensors correlation bank 1 sensor A. I replaced both of these sensors and code came back on after just 2 miles, and still aslight pop(backfire) type noise when It finally gets to 50 or so. Just basically hoping someone can elaborate on the whole meaning of the code for me as well as other things I might check. Thanks I am just trying to learn how to do things myself, Teri