Engine keeps trying to shut off when transmission is in park or when stopped and not it in neutral

Also was told its strait pipe no catalytic converter or oxygen senser to the end of exhaust. I think it's wat he said. Smoking out tall pipe, white smoke, new battery just replaced, and has hard time idling in park at times. But has been really hard to stop and I will have to put it in neutral at 4 ways' because it tries to shut off when in drive with foot on brake. Put it in neutral and it's usually okay for the most part. Has real loud noise from passenger side of dash when just turned off. And close to quarter of tank gas really starts acting this way. Something at times it doesn't want to switch gears when taking off from 0- 45 miles per hour it switches two but at times won't go third. Feels like the axils are locked back end. Heck I don't know. But it has amazing power and speed, and acceleration. Press the brake and it's like it wants to keep going and tries to shut off if not put in neutral then drive to go again.