help me identify this hose

It's part of the evaporative emissions system. Basically, the gas fumes in the gas tank are collected in the charcoal canister in the passenger fender. That hose goes to that cylinder there at the end of the hose; that's called the CANP solenoid. The other end of the CANP should have a vacuum hose leading to the intake manifold. Basically, it collects gas fumes and vents them into the intake manifold. If you've noticed a smell of gas from the engine bay and there's no obvious gas leak, these hoses are cracked and need replacing.

It doesn't hurt performance in any way to have the system, you won't gain any HP by removing it. You'll need to remove the passenger wheel and the splash guard to get access to the other end of that hose.