So you had a shop do the t-belt. Do you have a list of the parts they replaced? I recently found out if it's not a specialty shop, doing the t-belt could be as minimal as changing the timing belt, which could spell disaster. Not to scare you or anything. At a minimum, the tensioner and two idler pulleys should be changed as well.
Just the water pump, I think grk nickafis pretty much nailed it. For non-OEM belts, I've found Gates and Goodyear to be best.
Also please add your location, and car type and year to your profile so it's easier for us to help you
. I know of many members in various cities and Z specialty shops as well. Even dealers aren't reliable service points for these cars, as many techs there have never even worked on a Z32.
For the crank pulley puller, you can get it from autozone or whatever on loan. But as Ace mentioned, it can stay on for a water pump swap out. So can the lower timing cover, by default.
Your bad sensor could be your MAF, which may need to be cleaned or replaced. Replaced they're about $430 new from Nissan, but Specialty Z sells quality used ones for about $150. Is your check engine light on? Did you do an ECU diagnostic to see if it's throwing any codes? Twinturbo.net has the diagnostic in their Tech pages section. Dunno if it's on here, but it may be as well.
Speedo and Odo intermittent fix
Also, be sure to put some rags below the water pump to prevent coolant from getting on the timing belt.