Mine have never been right from the get go. Had the dealership perform the service bulletin/recall on them in 2009 and they still all read about 2-4 pounds low. Also, on cold mornings, I will get an under-inflation warning on one of the tires, say the RR at 35, and the LR will read 34 and no warning will be given for it. Makes no sense so I stopped paying attention all together and just check it the manual way every month or so.
1967 Firebird 400/4spd all numbers matching
1965 Pontiac GTO 389 4bbl 4sp.
1971 Camaro Pro ET Drag Car
1970 Camaro real Z-28
1963 Impala Super Sport 409 dual quad 4 spd
1967 Chevelle SS396 4sp clone
2009 White Pontiac G8 GT.........shockingly stock.
(My wife says I have a problem)