GM-GMC: gmc sonoma backfires, gmc sonoma, crank case

Question
why does my 96 sonoma s 15 backfires and hesitates under load

Answer
my guess is your engine is gunked up. use some seafoam.. you can get it at walmart cheaper then anywhere else... i use it all the time to keep my vehicles gunk free. you can use it in the crank case and the gas. run that for a while and see if it doesnt help.