i have had my autometer cf machanical boost gauge 4 3 months now and it has worked fine yesterday i noticed that now it just reads lower it use to read 20inHg at idel now it reads 30 and it boosts lower now the car is running fine and feels just as good as ever

 

check for leaks or your gauge is toast. Autometers are pretty crappy but you get what you paid for it.