I used to have an 01 dakota with a 3.9 and the oil pressure guage was very responsive to engine rpms. Idling the gauge would sit on the lower hash mark and at highway speeds it would hang at the upper hash mark. I just got an 03 dakota same motor and the oil pressure stays right in the middle of the gauge at any rpm cold or hot. Sending unit possibly bad? Thanks Kelly

 

My 04 does the same thing. I was told that Dodge,sometime in 2002, changed the sending unit so the oil pressure stayed in the middle of the gauge to make some people less nervous about their oil pressure. In essence changed the gauge to an idiot light