I have a 2001 mustang gt 4speed with a kenne bell 2.1 supercharger on it. And i have a fuel pressure, boost,and air/fuel gauge. And my gauges are reading weird. My fuel preasure is normally at 80 and will go to 90 and sometimes even more while i drive and it will drop down back to 80 once i let off the gas. And my air/fuel gauge reads around 15 and will go lower once im on it. My tuner says " oh the gauges you got are just junk". But i dont know because why would multiple gauges from the same company been completly wrong. I just honestly dont trust the tuner very much but i am stuck with him because where im at there are not really many places around where i live that do this kind of work. The gauges i got are from Glowshift. Can someone please give me some advice.