I own a 2005 Chevrolet Avalanche Z71 with a 5.3 liter Z engine. I've been experiencing intermittent no oil pressure problems. Engine has around 120,000 miles and have been using Mobil 1 10w30 oil with AC Delco filters. On startup on three separate occasions there has been 0 oil pressure, no oil pressure warning on message center and upper engine clatter. I just changed oil and thought problem resolved, but it happened again today. Looking for help

 

Faulty sending unit.