there are two oxygen sensors mounted in either the manifolds or close to the engine in the y pipe . 1996 and newer have 4 or downstream sensors after the catalyic converter
The 1500 holds 25 gallons.
It should have 2 and they are screewed into the exhaust system/Pipes.
1995-1999 3.9L, 5.2L, and 5.9L Dodge Ram 1500 has two O2 sensors. One upstream (before cat) and one downstream (after cat).
The 2007 GMC Sierra-1500 has 16 valves.
The 2006 GMC Sierra-1500 has 12 valves.
The 2004 GMC Sierra-1500 has 12 valves.
The 2002 GMC Sierra-1500 has 12 valves.
The 2010 GMC Sierra-1500 has 12 valves.
The 2001 GMC Sierra-1500 has 12 valves.
The 2014 GMC Sierra-1500 has 12 valves.
The 2013 GMC Sierra-1500 has 12 valves.
The 2005 GMC Sierra-1500 has 12 valves.