I have a bone stock truck and lately it has been registering 1.5 - 2 psi at idle in gear or out of gear. WOT I get about 25 26 psi which is normal for my truck. It is an autommeter phatom series gauge about 2.5 years old. I first noticed this last winter and then in the summer it was normal 0 at idle in gear or out of gear. I do notice when out of gear and I push on the go pedal it will drop a little then go up, it does it very quickly. Is this a sign that the gauge is bad or something is wrong with the truck? The truck runs great. I appreciate all replys thank you.

 

Check your grounds and connections.

 

madhat I had a problem a year or so ago with my trans temp jumping so O soidered all my connections. I thought boost gauge was vacum or preasure and the wires were only for the lights? Thanks for the reply I will recheck the wires again.

 

You are correct. You should be able to run that gauge with no power leads hooked at all.

 

Good point... I'd pull the end from the intake manifold (or, where ever you have it mounted at,) and put compressed air on it, a low PSI, and watch your guage. I assume that you checked your line, I'd put a little soapy water on the connections and see if you have a leak. Always start with the cheepest thing first... maybe the line took a poop?