I have a 1996 Chevrolet Blazer with a 2001 motor. Fuel pump went out. Replaced fuel pump as well a plenium gaskets and fuel filter. Crank shaft sensor was also replaced although person working on vehicle now does not believe that this was necessary. Everything we have read online says to do a relearn however if my blazer has an anti-theft feature we do not know about it. Have never had a security light on dash. Is it possible that we still need to do a relearn? If so, how do you do this if there is no light in dash to come on or flash? Also, we have done all of the wiring tests and injectors are clean and appear to be in good working order. Completely at a loss on what we should try next if relearn is not an issue. Thank you for your help!