When I crank up my car, it sounds like it's humming.

sounds crank sensor, I had sunfire do the same on a bad cam sensor too

Sounds like a problem with crank, cam or the knock sensor.

This could very possibly be the antitheft system failing. Gm has had issues with this system since the 80's. When the system fails, the car will crank but not start. Might run for a second or more and then die. If these symptoms sound similar to yours, the antitheft might be the issue. Also look for a light on the dash that says SECURITY or ANTITHEFT. This is a telltale sign of an antitheft failure. This link explains the problem and solutions to fix this yourself.

http://vatspasslockpasskeysecurityhelp.yolasite.com/

It sounds like it might be a bad crank sensor. Although I had a sunfire one time I was working on that did this from a bad ignition switch. Check for power on the pink/blk wire at the ignition module plug with the key in the run position and when cranking the engine. Also do you have a security light flashing?

what is getting power and whats not? headlights work? horn? turn ignition switch on. lights on dash light up? crank car, cranks? no crank? cranks but wont run? ck eng light comes on when key on? clicks when turning ket to crank?

This may sound really dumb, but check your fuel... The 00 to 02 Sunfires had a problem with the fuelguage reading inacurately. Sometimes by as much as 1/3 of a tank. If not that then start at the basics, look for fuel getting to the engine, and spark... If the fuel pump is the culprit you can try having a partner hit the fuel tank with a rubber, or NON METAL hammer while your cranking the engine. If the car starts then dont risk it not starting again, get the fuel pump replaced right away.

You could have a bad pump motor in your fuel pump. You will hear the "hum" of the pump motor but it won't continuously feed enough pressue to the system.
When you prime it the engine will draw enough to run for a bit then quit. They usually dry out if not kept full and sunfire fuel pumps are noted for this type of failure.
Try a used one for about 75 bucks. My kids Sunfire did exactly the same thing.

its a sunfire , have a buddy sit in your car and you go to the back have him turn the key to the on position... not the run position and listen for a buzz or whiiirrrrrring sounds, do this several times if no noise chances are your fuel pump is dead, a common chev problem, if it has no noise you can try giving it a few good whacks where the fuel pump is located at the tank and try again more often than not this will get your fuel pump buzzing again and then you will know if your problem is at least in the front or the back..
yadidimean
Thanks Shawn

Does it crank at all? If it doesn't even crank it could be your starter.

Hi, I had the same problem with my girlfriend's 97' sunfire, it wouldn't start so I jumped the starter terminals which I think screwed it up even more (causing the theftlock light to come on). It turns out this is a common problem that can be solved by hooking up a GM Tech2 scanner, going under "body" codes, and following the instructions for bypassing the PASS LOCK SOLENOID. Hope you find this helpful, Byron