Boost drops to 0
 

Hey guys I just bought my first 12v. It's a 92 d350 that pretty much stock except for the exhaust. I just got my gauges installed today and my boost will get to about 12ish and stay for a second and fall to 0. No smoke or change in power or egts. Egts are at about 700 wot in fourth. Probe is in the down pipe ( was already a bung installed there when I got it). I put the boost line going into the plug just below the intake elbow. They are glowshift gauges and that could be the problem. Any ideas? Would a leak cause a complete drop? Wrong location?

check your line to the gauge, and yea glowshift are cheapies, and is that 12 at wot going down the road? a boost leak wont usually cause it to fall off like that