Hi,
I had similar issues with my 1999 T16 +4, and before you go spending any money just check the fuel filter. Just unclip it from its pipes, empty it out into a jar or something, and see if you can easily blow through it. If you can't, get yourself a new one. (If going to a motor factors or standard parts supplier, ask for one from a late 1990's Rover 800). As I've said before, mine was really choked with brown crud so I replaced it and it made quite a difference to the pick-up and general running - as you'd expect.
Also see my previous post about removing the restrictor plate that's welded to the inside of the main silencer, as reccommended to me by Chas Windridge. That too made a BIG difference!
