Also as far as torque and pattern I would invest the 20-30 bucks into a Haynes or Chilton manual for the truck it has this information and much much more in it I have one for every vehicle I own ( except my peterbilt )
Pete, 1990 will be EEC-IV. Autozone and the like are rarely equipped to read codes on anything that is not OBDII.
Triumph, where about are you located? There may be a mechanically inclined member near by who can help you first hand.