I have an 04 oldsmobile bravada. It won't accelerate or do anything at all when I depress the accelerator pedal. It will crank an idle like it is supposed to but that'* it. When I scanned it two codes came up p2127 p2138

This is kind of tough to diagnose without a scan tool capable of reading throttle position data and accelerator pedal position data....with a scan tool, you observe the data as you move the harnesses attached to them and observe the data...

Otherwise all you can do is a visual inspection of the connectors in the harness.....

When these codes set, the PCM commands the throttle plate to a set position......you can't accelerate past this position....it'* kind of a limp home mode....it'* also dangerous to drive, because you can't accelerate out of a potential problem....

What Tech II said above ^^^^^ plus, in the event that it'* not feasable to get your hands on a scan tool etc.:

This tells me the PCM can get the car to idle, therefore it is placing the throttle plate well enough to do this. Pressing the accelerator pedal with zero results could be the accelerator pedal position sensor or something wrong with the throttle assembly.

If the accelerator pedal sensor has gone bad, all movement of the accelerator pedal will not be sent to the PCM so it would never know that you wanted it to do something. In that state it would wait at idle until told to do otherwise.

If the throttle assembly has failed, it could be unable to move the throttle plate or unable to sense where it has moved it. It could be sitting there stuck at the position it was in right before the engine was shut off the last time it ran before failure. That would be lucky but not unlikely. OR it could be opening it enough for successful start then going "uh oh I can't see where it is, I'll go to a protected state where I'll keep the engine running but not do anything else for fear of placing the throttle plate inaccurately and causing bigger problems, damage, or safety issues."

Fortunately, you've scanned for codes:

These tell me that the Throttle Position Sensor is reading inaccurately. My guess here is that (1) the throttle motor is failing and therefore unable to place the throttle plate as commanded, or (2) the throttle motor is fine but the TPS is reading incorrectly, so the throttle motor is capable of placing the plates accurately but the readings from the TPS don't tell the PCM usefully that it did.

On many cars the TPS is a separate part that can be easily screwed to the side of the throttle body. Looking at parts online, it looks like yours has the TPS integrated with the throttle body assembly. If it were mine or one of my friends' cars, I'd recommend verifying the connector at the throttle body as well as the wires leading to it. If those are good, I'd recommend taking a chance on replacing the throttle body (with its integrated TPS). It'* a $150.00-$200.00 gamble, but it seems the most likely culprit from what I can tell.