With 2005 mountaineer i have replaced front wheel hubs and both front sensors truck seems to loose power sometimes also turning to right hear agrinding noise

have youre transfer case checked

If same tires as before & air pressure set correctly, or as usual, a humming when swerving, or turning one way or the other or both, it's usually a pretty good indicator.

Check rear wheel bearings for condition and adjustment. Check front axle "U" joints or cv joints for serviceability especially at the turning point for the axle stubs.

I had the same problem with my 2002 Mountaineer at about forty thousand miles. Murcury replaced the steering column free under warranty. I now have ninty two thousand miles and it's back. The rear end is making a whining noise, the tranny is starting to slip, and the rear window regulator went out. Why did we buy a Mercury?????? Disgusted Dave!!!