1999 Town And Country 150k miles automatic limited 3.8

Aloha picked this car up for $300. Dude passed away, and was given to his daughter. She had it brought to a shop who said it was fuel pump. She didn't have the $600 to fix it. It sat there for 6 months then I bought it for $300. 

I brought it home, changed the fuel pump. It now starts. No engine lights. I did use code reader too, no codes. 

But when I give it gas, like pushing almost halfway on pedal, it will make a popping sound in the front and struggle to accelerate. If I barely touch pedal and take off slowly it doesn't really do it. When I get up to speed slowly to like 60mph and continue to barely touch pedal, it doesn't do it. Also noticed it will also sometimes make the popping sound from the rear, almost sounds like its coming from exhaust or the gas tank itself. 

I remember going to look at a car that sat for a couple years once, and it started right up and also made the popping sound in front. The owners looks very confused as they said it didn't do that before it sat.

I replaced fuel pump and fuel filter. 

I was driving it around a few days like this but after a while thought it might not be safe.

Wondering maybe fuel pump I bought is defective or something wrong with it. Lmk what ya think

Appreciate the help ty