Where is the mass air flow sensor on a 98 Ford Explorer sport?

On a 1998 Ford Explorer Sport, the Mass Air Flow (MAF) sensor is typically located in the air intake tube, between the air filter housing and the throttle body. It's a relatively small, rectangular sensor with a wire harness plugged into it.

To be certain, you should consult a repair manual specific to your 1998 Ford Explorer Sport. A diagram will clearly show its location. You can often find these online as PDFs or through auto parts stores. Looking at pictures online of 1998 Explorer Sport engine bays might also help you visually identify it once you've opened the hood.