Will it matter if I change my pressure cap on my car?
My car’s engine cap (not radiator cap) is all rusted. I have one almost identical but the pressure is .1 lower.
My engine cap is 1.0 but the one I have is 0.9
It is impossible to find the correct one for my car
I've noticed the same thing as you. Radiator caps and thermostats are impossible to find. Toyota's rating on thermostats are in Celsius instead of Farenheit. I converted the rating over and found that they're only a 180 degree thermostat.

Exterior Modifications: