Have a 2005 NPR, The air wasn't working as good as it was a couple of weeks ago and the compressor belt started making noise when the compressor would kick back on after cycling. I hooked up a set of gauges. The high side started rising to 450psi, the low side was at 32 psi. I have never seen high side pressures that high. When the pressure gets this high is when the compressor belt squeaks at start up after cycling. Any help would be greatly appreciated! Need asap! THANKS!