Anybody tell me what this is for? Is it the ECM power? There's one red and one orange wire going to it, and it looks like it's supposed to have a weatherproof cap, but it's gone.

 

That is the Fuel pump relay fuse, without it the fuel pump won't work.

 

To add to that, if you have it, it's also power to the MAF power and burnoff relays plus, it's also the main/constant power to the ECM.

 

Are you serious??? I've been screwing with a code 36 for the longest damn time. If that fuse holder was corroded and not allowing all current to go through, might it be responsible for that code??? I replaced EVERYTHING except for the ECM! Might this be it???

 

Believe it or not, I'm serious.
Honestly, if the power/connection at the fuse is bad, you'd have more problems than just a code 36.
Code 36 relates to the MAF burnoff circuit. This can be anything from the MAF burnoff relay being bad (which I've seen being a problem more than once on here) to a problem in the circuit supplying the power to it (the relay).

 

But here is the catch...if that fuse is not allowing power to go past it, the car will not start!