ok this one is strange my daughters 2000 blazer had a random miss fire i replaced cap,rotor,plugs,wires,spider injection and ignition switch it never had a problem starting until it got into a small fender bender my daughter hit some guy in the rear end of his truck. after that it will only crank but not start i have spark to the plugs and have fuel im ruling out compression because it drove home ok minus the misfire even tried starting fluid still no start. now when trying to start it after i let go of the key it will then act like it wants to start i get a quick chug then nothing. is there any kind of wiring at the front of the blazer that could cause this any help would be grate. and the security light does go out after like 5 seconds i know if it stays on then that's the problem is there any kind of safety switches that could cause it to not start but still have spark and fuel. Thanks

 

Could be a problem with the ignition control module.