once i reach about 45 mph, my suv loses power. i think it is the oxygen sensor. if so, can i clean it as opoosed to a new $350 one or is it something else?
Why do you think it’s the oxygen sensor? Does that seem like a good guess? Well, it’s not the problem.
Is the check engine light on? If it is, have a mechanic scan it and determine a course of action (troubleshooting).
A fall off of performance is, often, a result of loss of fuel pressure/flow. Change the dirty fuel filter, and check the fuel pressure. After that is done, there are other checks to do. Let us know.