help 2000 sr20de chokes and stalls

need help guys 2000 sr20de 72k, complete tune up, new o2sensor, revs fine over 2500rpm as soon as it drops below that chugs and will not excelerate. then chugs itself to a stall. slight smell of gas by the fuel pressure regulator. but checked and is fine.

Hmmm, interesting. Well, it would help if I knew anything you had done to the car recently, and why you replaced the o2 sensor. If your o2 sensor was fouled you might be running rich. If this was the case, now that you have a new o2 that works, it is probably telling your computer to lean out the mixture. I don't suppose that fuel pressure regulator you spoke of is adjustable. You're playing with fire when you adjust those. or it could just be a problem with your MAF/MAP or your CTS which are also key factors in how much fuel the engine gets.