I swapped a 01 bravada engine into a 97 blazer and my oil pressure sits at 20 cold and slowly goes down to around 10 when it is warmed up. I bought an aftermarket oil pressure sensor and I went to check if oil was bypassing the sensor and getting on the plug, while I was doing that the plastic part disconnected from the medal thread part so it no longer works. I put 10w-40 in it and it seems to be running slightly better. I am close to changing the oil pump but I was wondering if there were any other things that I should check before then?

 

I've never had that particular problem but it does sound like your pressure is low.

I couldn't tell from what you wrote if you were able to confirm the actual pressure was low or not.