The gauge reads fine in park, no issues. How ever in any gear other then park the gauge doesn't work, it reads zero or flutters around, maybe reading right for a few seconds. The reading in park is pretty much normal, this started after I got my speedo gears in the trans fixed. It maybe unrelated or not, I'm waiting for the car to cool down and unplug the sending unit, if it pegs out past 80PSI I'll know it's an issue with the sending unit and not the circuit. Any other ideas?

edit: Keyforward with sending unit unplugged maxes the gauge out. circuit seems fine.

 

replace the switch. it just sounds like it has gone bad.

 

Just picked one up and the special socket, whats weird is, it seems to be working fine now?

 

yup its the pressure sensor, typical 93 issue before they relocated them to behind the manifold i broke mine when i gutted my cat years ago, and when i worked in the shop i saw a couple get broken when doing any exhaust/ trans work. you dont need the special socket though, i always used channel locks cause you dont want it very tight. just remember to put sealant on the threads.