Yeah but I don't understand why - because any toyota or other engine i've seen that runs on around 5 psi at idle is a broken one, it can't keep up at mid to high revs and the engine dies. Toyotas usually idle at min 15 psi when warm and go upto 65-70 psi during the normal course of driving...
it would be a good idea to get a proper mechanical gauge that fits inplace of the oil pressure sensor and comfirm OR install the old oil pressure sensor and see if any change in behavior
you also mentioned replacement of oil filter housing - was it a used or new part?