I have a 2003 Ram 2WD, 5.7 Hemi. When first started cold it has good oil pressure. After a few seconds, the needle falls to zero. motor sounds as if it's still getting oil but I'm not sure. any ideas as to what could be going on?

 

Check your oil level and replace your oil pressure sensor.

 

Replace your oil filter also and could also be your oil sump sucking junk up and plugging up

 

I've changed oil and filter. I wasn't thinking of the sump pump. I'll pull the pan and check. I was thinking it may be stacking the oil on heads, not returning to pan. I've never changed sensor on Hemi, is it hard to get to?