For a while now my 1998 Honda crv has been giving trouble, A few weeks ago the car would just shut off and would not start and my dad and I changed the spark plugs and the car went back to being normal, just recently it hesitates when I accelerate and then catches a speed, so last time that happened it was a dirty air filter, it is happening again but I changed the air filter again it worked or a little while but it start t hesitate on acceleration and catches a speed, when accelerating it sounds like it wants to shut down, makes a lot of backfiring sound and like it has no power (it sound like dududud and then it speeds up on its own, but the weird thing is when I put the car in reverse the idle drops lower and lower then it stalls, one time when I was restarting it, it was just cranking and not turning over, I primed the fuel pump by turning the ignition on and off then it finally started, it did a little research and saw that if it stalls in reverse it could be IAC. I cleaned out the IAC a while back and it was giving trouble for a long time now but it never affected to stall the car in reverse. I suspected it to be a failing fuel pump, I would like your guys opinion on what the issue may be but I have Strong feeling it is a failing fuel pump. Could you guys give a second opinion? 

It is a 4 speed automatic 

About 300k kilometers