This truck was the pumper at Happy Valley, was taken off the run as unroadworthy in 2006, it had severe rust in the chassis. One would assime then that they did a LOT of work to it, you might want to get someone to check that out. I don't beleive the slow bit, that truck was a rocket when we had it, but if its been sitting for 3 years then that might be a problem, we used to have to take it for regular drives to blow the carbon out, but otherwise it was fine.
Still, 22 years old, any truck at that age would be over it.