losing power when accellerating

the issue started a while ago before i put headers and removed the cat and all that anyways what would happen is when you hit the gas it would just choke out and the engine would die out but when you let off and gave it a little bit of gas it would go so i thought maybe the exhaust was clogged up at the cat and resonator and put headers to 2.25 piping all the way back to a canister and it stoped it would accelerate fine but just recently like last week it started happening again but instead it happens in low idle itll go to about 1500 2 grand before it chokes and starts to lurch and not get power i have an auto so im not sure if its the transmission or the fuel pump or filter can anybody help its kind of hard to explain but i tryed my best