Will I need a special sensor socket or wrench to install this?

An oxygen sensor socket (22mm or 30mm, depending on your model) makes removal and installation much cleaner, but a standard wrench works if you're careful. The sensor threads directly into the exhaust manifold or exhaust pipe at the factory location — no modification needed.

Does this sensor come pre-gapped or ready to screw in?

Yes, it's ready to install straight out of the box. Just apply a thin coat of anti-seize compound to the threads (especially if your exhaust runs hot), thread it in by hand first, then torque it down snug — refer to your service manual for the exact torque spec.

What if the check engine light came back after I installed a sensor before?

A new sensor won't clear a stored code on its own — you'll need a scanner to clear it after installation. If the light returns immediately, the issue may be elsewhere in the fuel trim or emissions system. A failing catalytic converter or vacuum leak can trigger oxygen sensor codes even with a good sensor in place.