Yours must have been damaged from the factory, or a mislabelled return I guess. It can happen. Mine work fine, still do 4 years after I got them. They’re mostly accurate, within a pretty good tolerance like +/- 5% or so like most other torque wrenches. Nothing compared to Precision Instruments, but Pittsburgh won’t kill the bank like PI will. PI is the best for torque and other precision related tools, but they’re rather expensive.

Again, the most important thing is to calibrate it and check its calibration before use. This goes for all torque wrenches. Also, always store the torque wrench set to zero, never at any number other than zero. As soon as you are finished torquing the fasteners you need to, set it back to zero. Basically try to keep your torque wrench set to the torque you need for the least amount of time possible. Doing so keeps it calibrated longer and in the best shape it can be. Do not use the torque wrench to break fasteners loose or to tighten fasteners snug. If you have to ratchet the torque wrench more than about 2 turns (unless you like the bar-type like I do), just switch to a regular ratchet, unless the required torque is approached. Also keep in mind wet and dry torque values are different.

I have never over or under torqued a fastener with a Pittsburgh torque wrench, or any torque wrench for that matter.