Where is the MAP sensor on a 1996 Suburban 5.7L engine?

Here's what it looks like, which should help you locate it:

AutoZone.com | Vehicle Selection | Year (http://www.autozone.com/autozone/catalog/parts/partsShelf.jsp?categoryDisplayName=Engine+Manageme nt&fromType=parts&fromString=search&parentId=cat10014&currentPage=1&filterByKeyWord=map+sensor&navValue=15900127&categoryNValue=15999999&fromWhere=&itemId=prod10697&displayName=MAP+Sensor&searchText=map+sensor)

Likely, it's either on top of the plenum or along the firewall, with a hose going to the throttle body.