When you immediately start the car the gauge works fine and is reading between 30 and 35 PSI. After it warms up a little bit, it goes down to 10 or 15. Then it starts going wacky going from 0 to 60 at a million miles a minute. Already change the sending unit twice. Put a manual gauge up to it and it's reading fine. Is it my gauges? Or is it something else? I need some help on this guys

 

I have 92 formula, and mine does the same thing. cold start it's at 30-35 once warmed up it's around 10-15 but it's not bouncing all over. I was wondering myself if that normal to go that low. I just got my 3rd gen about a month ago so i'm new to it.

 

Sounds like the gauge is going bad, or there is a wiring problem, maybe a ground issue

 

My excellent condition 86 LB9 is over 60 psi at startup, and never drops below 25 at a hot idle (600 RPM). I run 10w40 Amsoil PP. But a single weight of oil thicker isn't going to bump it 15 psi either.

Test with a calibrated mechanical shop gauge if you really want an accurate reading. The general rule of thumb is 10 psi per 1000 RPM of engine speed but generally in my experience if it's below 20-25 psi at a hot idle your clearances are opened up.

GD