p0200 error code

[mogie]

Hi all,
Just bought a hummer 2003 h2 off auction. I had the key stuck in ignition issue. Fixed it by cleaning the solenoid. Then it would stay in 3rd gear according to the instrument panel no matter where I put the shifter. I realized it must be disconnected from the tranny. I crawled under the hummer and reconnected the shifter. I need the clip that holds that in place by the way if anyone has a part number. So now I can get it into park.

I put in a new battery and attempted to start it. I got p0200. I know it has something to do with injectors. It tries to start and dies almost right away. I also got some codes relating to MAF and air sensors but I reset the codes, tightened the air intake (was loose) and am still getting p0200.

Where should I begin? thanks!