boost gauge flicker?

[ATLDSM96]

I have a Glow Shift boost gauge that i got from a friend. how come it flickers under vacuum. it doesnt do it under boost? the only conclusion i could come to would be buy a boost gauge worth a crap. any suggestions are welcome.

thanks Robert

 

[CTP]

Where do you have it sourced from and what else is on that line?

 

[rossb]

what flickers? the lights on it? or the needle jumps around?

 

[ATLDSM96]

its spliced into the P hose on the throttle body. the needle it self jumps and i hear a tick under my hood when ever the gauge jumps.

 

[Defiant]

Look for a crack or kink in the sensing line.