i have the quad rail gauge but im no longer using it for rail pressure but just lift pump pressure.it used to read 6-9 all the time. now it fluctuates rapidly between 0-8 psi fast. it actually stays on 0 lots nowand then the odd time it says 7 psi. do i have Lp issues or are quad engineers at fault?

 

Do some searches and you WILL find that the sending unit is the problem....

 

can i get a free one?what is a napa substitute?#

 

any1? is there a napa or autozone replacement?