i would disconnect the line from the keg, bleed the keg down (how long have you had it under excessive pressures?- that might be contributing to excessive foam too) and see what your gauge does. If your reg is bleeding through, it will bleed pressure to a closed valve the same as it would to a keg full of beer. Hopefully it doesn't go high enough to burst your lines or connections. Regulators are a little touchy, and take some time to adjust to when you tamper with the set. When you turn them back, the pressure won't drop until it has someplace to go, and when you turn them up, the needle doesn't always reach it's peak right away and stop- sometimes you will have a little bit of residual climb. I would tweak things unconnected so you are not saturating your beer. you might want to get a different gauge for your low side, too. A gauge with a smaller scale (say 0- 20 psi) is going to be more reactive to your adjustments then one with a larger one (like 0-100) - though it will be less forgiving to 40 psi, and if you bottom it out hard and bend the winding, you may have to replace it.