Reset security 2001 chevy blazer 4.3l

Changed out ignition and had to reset the security system started but ran horrible. So then changed out fuel pump crankshaft sensor plugs wires distributor cap rotor. And it will crank but not start. What could be wrong

Make sure battery has a full charge and connections all good. Have a helper crank it while you check for spark at the plugs? If spark everywhere, use a gage and check proper fuel pressure? Check fuel injector pulse? Any applicable trouble codes? Those are the basic checks, in my opinion. Let us know if your missing anything or everything just mentioned.

Mine THINKS it is out of gas. Gas gauge dropped to EMPTY. It wants to crank but won't. I know I have about 1/2 tank of gas in it. Does not seem to be the Fuel pump - I do have spark. So..... WTH??? Otherwise, nice vehicle with many upgrades.