i have an 87 pu and the needle usually sits just underneath the middle mark. but now its sitting lower and when it is at idle it goes below the first mark. is this normal?

 

I don't know about Toyotas, but generally speaking, factory gauges are little better than dummy lights. Many don't have a linear sweep and only register as "normal" when the pressure is above some minimum psi. I would get a cheap mechanical gauge and see what the pressure really is.

 

This is normal for an engine that is warmed up, yes