1999 or 2000 malibu wont start

hi guys my girlfriend has a 199 or a 2000 chevy malibu. it wont start i have changed the battery and i have changed the post.also when i turn on the car the lights and everything comes on but when i crank it it does like it wants to crank but wont start. what could this problem be. help

4 or 6, also do you mean the engine turns over but will not fire?

Its a6 and it wont fire

Its possibly a camshaft position sensor.

I wouldn't be jumping at a camshaft sensor....

Check for codes....

Check for spark.....if you have spark, spray carb cleaner into the intake and see if it starts.......

Check for fuel pressure.....check to see if injectors are firing(Security problem)...

Check compression....