I am installing a set of autometer elec gauges in my 1973 z28 and having a problem with gas gauge. i wired it up and the neddle is peged well passed the full line went i start car up? and when i shut car off the neddle doesn't move.

 

Usually caused by having the wrong restistance between the gage and the sender. Should have been some instruction with the gage? Might fine something on line.