Looking For Service engine soon code 4

Looking For Service engine soon code 4.

specifically, shows loosing oil pressure down to a few lines under 40, starts up ruffly, and while in R, Over D, D and at a complete stop it wants to stall out with some "chugging"while in park or neutral it stays running.
while moving if the S.E.S light comes on going to neutral when possible for 10 secs give or take turns it off and when you return to Drive it runs normally, like it does 85% of the time Besides while at a COMPLETE stop and in a moving gear.

Thank you for your help, wish to come here more often when poor luck wins out, and a well made site.