Vacuum Gauge Needle Vibrates At Idle

[DSM AWD TSI]

Hey guys,

My aftermarket boost/vacuum gauge (mechanical) needle jumps/vibrates at idle like it's trying to switch between -7 and -18 hg vacuum so fast that the needle can't move that fast and it just vibrates between -11 and -13 vacuum so fast the tip of it blurs. If I push on the throttle a bit, it will smooth out and goes as low as -20 and is smooth throughout the rest of the vacuum/boost areas. Could it still be a vacuum leak even though its smooth in non idle vacuum? Also, the car idles relatively smoothly, with a little engine vibration but that's probably from the not-so-great condition of the motor mounts. Any input on what to check or what to do about it is greatly appreciated! Thanks.

 

[rush2252]

I would say check all your connections first. Then boost leaks.
How do you have the vacuum line ran to the gauge? Did you T it at the manifold or where did you run the line from?

 

[DSM AWD TSI]

I T-d it off of the vacuum line to the fuel pressure regulator. Sorry, I meant to put that in the question part but forgot, can't remember so much info at once

 

[Defiant]

IWEMA enterprise, How to use a vacuum gauge.