Where is the smog pump on a 2001dirt Chevy s10 4x4?

A 2001 Chevy S10 4x4 wouldn't have a smog pump (also known as an air injection pump). Smog pumps were phased out on many vehicles, including most S10s, by the late 1990s due to stricter emissions standards that favored other emission control technologies. The specific year they were discontinued varied by engine and region. If you have a specific emission control question, it's best to check your vehicle's emissions label (often under the hood) and consult your owner's manual or a repair manual specific to your truck's engine and year.