unsolved misfire 99 firebird

[ravermade]

I have been having misses in cylinder 6. I've replaced all coils, plugs,wires,airfilter,and just today had a mechanic replace the fuel injector, but now its got alot worse and when they gave it back the security light is steadily on but the car still runs. What could the miss be caused by and could something they did trigger the security light to come on?

 

[melsg5]

do you have a check engine light on? did the mechanic do a compression test? Security light is probably a separate issue, did the mechanic disconnect the battery?