hesitation

i was given a 99 blazer LS as a gift and im trying to iron out the "little things" the air bag lite goes on and off and after having it checked they said it was the module and i needed a new one..module and labor over $500..umm ..any other ideas...next problem...there is a definite hesitation at hi way speeds..is this fuel injection? i bought some of that injector cleaner..havent tried it yet..any ideas? :banghead:

more info on teh truck would be nice. Give some details on what exactly it does or doesn't do. What happened just before this occured, etc.

Robert