My 3.8 died so I decided to put a 4.2 in from an f150. Supposedly 150k miles on it and ran good when pulled. I did not hear it run unfortunately as it was already pulled. Install was very easy actually, i may do a thread on that, but I have low oil pressure. When cold at idle it shows around 40 then slowly works its way down to around 5 as it gets hot. I don't hear any valve noise or rod knock but it makes a slight squeaking noise when it gets to this point. I fear that the rod bearings are bad. Can anyone offer different opinions on that before i take the motor back out?