what made you decide its the crank sensor?I work at a chevy dealer and have for 18 years and have yet to see a crank sensor go bad in a v 8 like you have.it needs to be diagnosed by someone who knows what theyre doing or your gonna spend lots and probably never fix it.imo I would check for a fuel related concern as the ignition systems on those engines are pretty much bulletproof,not saying it cant happen but isnt likely.