Cat-back question

[GoTbOOsT]

I have a magnaflow muffler with a custom bent 2.25 piping behind the cat and no resonator. I got this doen at Meineke but the problem is that whenever I let off the gas and the RPM goes below 2000 i start to hear POP POP POP from the back of my car. I know its caused by back pressure but is there anyway to eliminate the noise?

[Kaioshin1982]

i get the same popping noise