1996 Altima GXE. The far starts fine, no check engine light, it idles fine, but step on the gas, and it stays at idle. I've reached in the engine area and manually moved the throttle, but still nothing. I don't know a whole lot about Altima's (working on my friend's car) but I see 2 'throttle' cables, one goes to the gas, and the other goes to a little black cylinder on the back wall of the engine bay.

That cable does not move freely when the throttle valve is turned, I have to 'force' it into it's case. I'm ASSUMING that's the problem? (but we all know what happens when you ASSuME.) I don't know what that is, I can't find any information pointing me in the right direction, but, what is that?

And if anyone knows anything else that might be the problem? please help....

Welcome to NICO!
The cable going to the black cylinder is cruise control. You can try disconnecting it from the throttle to see if that cures the problem.

Did you say you can manually move the throttle (even with the other cable connected), and it still doesn't rev up at idle? If so, you're going to want to remove your air intake, and take a peek in there while you move the throttle. Maybe something broke somewhere, and you moving the throttle pulley isn't translating to moving the butterfly valve inside the throttle body. If that's the case, you'll need a new throttle body and gasket. Should be pretty cheap from a bone yard.

Wow, I'm blind. It was the linkage between the throttle pulley and the throttle body. I've popped this off on other cars, I should have noticed it wasn't connected... I guess that's why I'm not an auto mechanic Thank you got your help....

Glad you got it sorted out!