Need quick advice-oil light came on!!!

[sfm7315]

Hello everyone I need some expert opinions asap!!!!.
This morning while doing about 65mph on freeway the oil light came on!
I pulled over and checked oil -it's fine. Just had it changed at dealer last week. Engine runs smooth -no issues . I took it to dealer they had it all day checked it out no visual problems but I have to bring it back tomorrow because the told me they need a speacial adaptor to fully diagnose it. Can someone give me ideas on what to expect before they try to hose me!!
It's a 98 4Runner Limited 133000 miles on clock

 

[beallen21]

oil sending unit? maybe

 

[sfm7315]

Hello all, just had dealership change oil sending unit on my 98 4Runner Limited because oil light turning on.
They said oil pressure was: 8.1psi at idle-----normal
20-30 at 3000rpm--- below normal according to them it should be at 43minimum, is that true? and if so what could be causes?