Intake Air Temperature sensor 98 Honda Accord, where is it exactly?

its located on the driver's side rear of the intake plenum. the intake plenum is the aluminum housing with the 6 tubes that sits on top of the engine. the intake air temperature sensor should be screwed into the rear of that plenum on the back side (facing the windshield) and near the end that would be in front of the steering wheel.

those gas saving modules change the resistance value of the intake air sensor so that the control unit on board is "tricked" into thinking its okay to inject less fuel. the problem with those systems is that the onboard control system is too sophisticated to trick with such a simple change; the IAT value will be inconsistant with the engine temperature and other inputs and the control unit will self-correct to adjust for the changed values from the new module. Simply said, you'd be better off spending your money on a new air filter than on a gimmick.

hope that helps

Honda Iat Sensor

the intake air temp sensor will be located before the air filter on most cars.

Anything thats advertized on EBay is probably some pie in the sky gizmo. But go ahead and throw away your money. Its yours to do as you wish.