98 Ford Taurus Bogs Down

My secretary has a 98 Ford Taurus with 150k miles - she maintains it regularly and it’s in good shape mechanically. Recently she noticed that when driving at highway speeds the RPMs will occassionally suddenly drop and she feels like the car bogs down reducing speed. Could this be an O2 / EGR sensor or what are your thoughts? Thanks!

How old is the fuel filter?

If the fuel filter isn’t restricting fuel flow, the fuel pump could be getting weak.

I’m assuming no Check Engine light is on.

Like the others I would look at a fuel pressure problem first, either from a clogged filter or weak pump or both.

The I would look for any signs of exhaust system restrictions.

Thanks - no check engine light but she doesn’t remember changing the filter recently. I’ll have her do that and see if he helps. Appreciate all of your advice!