S-Type V8
I had the engine light come on this spring, someone told me to use 10w40 oil.
I did and no light came on, but when it got hotter outside the light came on again.
Electrical test for VVT Solenoid is fine.
Oil pressure test is 50psi, operating temp. is 10psi.
Always shows Bank 1 VVT retarded.
Is it possible that the oil pump is not good anymore?

Any help would be very much appreciated.

Thanks