I have a 97 bravada that i just changed a fuel injector in it was running before the change but misfiring on 1 cylinder then after i changed it it would not start at all checked fuses and fuel pump is running and there is fuel comin up to the engine but the injectors don't seem to be working has fire to the plugs as well. i took it back apart thinking i might have missed something and put it back together and it ran took it for a drive come back home parked it came out an hour later and wouldn't start and still won't please help need this thing goin asap