Installed a boost gauge on my 2002 HO today. Started the engine up and had a zero reading on the gauge. Obviously I've done something wrong. For installation I removed the 3/4" NPT plug that was just behind the fuel filter and right before a factory sending unit of some sort. Was that the right plug to remove? Could I have tightened the crush fitting too tight? I tried to make sure it was just snug not REAL tight. Any tips appreciated.