[Flyin' Hawaiian]

If you experience this deceleration when you're barely touching the gas pedal, it's most definitely the tps slightly out of adjustment.
I don't know if many folks out there have noticed just how sensitive the tps really is. When adjusting the tps, moving it (literally) just a hair will throw it off! Also, if you have any mods done to your vehicle, you'll probably find setting the tps to stock will not be quite right and you'll experience the problem you describe.
Personally, I like setting it by hand instead of using a multimeter and feeler gauge. I think I can get a smoother throttle this way...
Good luck in getting it set!

 

[Flyin' Hawaiian]

You have to have the tps for the car to run! Even with aftermarket fuel management, I think you still have to run with a tps-although I could be wrong about that one.
I posted somewhere a link to properly setting the tps with an ohm meter. Try doing a search on tps and you should have a bunch of info on the subject!