I got a 99 xj sport took it to work the other day and lost power going on a steep hill. I was able to make it up by gassing it hard. I noticed oil pressure dropped when this happened. Checked oil and levels were fine. It was able to make it home but oil pressure would go up and down at idle. It has new brakes new plugs and wires new cap and rotor and recent oil change. After that happened I changed oil pressure sender but haven't taken it up hill since then.