oil pressure

I have a 2000 cherokee and i took it in to the dealership last week because when i start it up oil pressure reads 50-55lbs but as I drive along pressure goes down and at stop it goes down to 5lbs. So the dealership puts a new oil pump in and guess what, that was not it. Does anybody know what is going on, they also tryed a new sending unit so it was not that. I run 10w30 oil. And like i said i have good oil pressure at cold start up. When I am traveling 70 mph my pressure is 20lbs and at stop it drops to 5lbs and the check guage light comes on. If i down shift i can bring the pressure up. Please help thank you

I have a 2000 cherokee and i took it in to the dealership last week because when i start it up oil pressure reads 50-55lbs but as I drive along pressure goes down and at stop it goes down to 5lbs. So the dealership puts a new oil pump in and guess what, that was not it. Does anybody know what is going on, they also tryed a new sending unit so it was not that. I run 10w30 oil. And like i said i have good oil pressure at cold start up. When I am traveling 70 mph my pressure is 20lbs and at stop it drops to 5lbs and the check guage light comes on. If i down shift i can bring the pressure up. Please help thank you
YOU COULD INSTALL A MECHANICAL OIL PRESSURE GAUGE SEPERATLY & GET A TRUE READING. THEY'RE NOT EXPENSIVE & THEY COULD SAVE YOUR ENGINE JUST INCASE THE ORGINAL GAUGE GOES SOUTH ON YOU.
DALE [email protected] :2cents:

If the pressure readings are correct, you have an internal oil leak. Worn camshaft bearings can produce this effect.