Since you're replaced everything else(almost), I wonder if the Throttle Position Sensor could cause this problem. I suppose it's possible that if the computer thinks the throttle is open, it could dump in a lot of gas, which might explain why you are smelling gas. It really sounds like you aren't getting air, or are getting a really rich a/f mixture. I've had this problem a couple of times, but it would usually clear itself up after 10 seconds or so.
I don't know, it's just something to think about. Good luck.
