This ^^^^^^^
I had fluctuations in my MAP readings on my G3X and just lived with it until I installed my P-Mag then I installed a snubber to smooth out the MAP variance. This is what I purchased...
Brass, 1/8 NPT Male x Female, 0.004" Orifice Diameter, PN 3820K11
I thought a .004 orifice might be too restrictive and cause a lag in my MAP indication, but it worked great! My MAP indication is rock steading and responsive to any power change. I did install it at the stock Van's transducer manifold rather than at the #3 intake to limit the possibility of the orifice becoming plugged. Then I used the plugged MAP tap to install a 1/8" NPT to 1/8" Male barb to connect my my PMag MAP tubing.