How accurate is autometer fuel pressure gauge?

[jimmmy]

I orginally had a fuel pressure guage on the sharder valve and it read 40 psi vacum off. Now i have an auto meter mechanical fuel pressure gauge mounted on my cowl and it reads 36 psi vac off.

The one i had on the sharder valve was one i picked up at an auto store. Is the autometer gauge more accurate?

 

[sgarlic]

An Autometer mech. is about as accurate as you can get.. I've never used any other brand of gauge and actually trusted it the way I do AM's.