Check Engine Code/Front end noise.

Just bought a 1999 Ranger Supercab w/4.0 - 4x4 - XLT w/tow package, and 68,000 miles. Check engine lights on so I had the code read at Auto Zone, but I forget the code. However - tech said it was the "second stage" O2 sensor "on the cat convertor". I'll be going back to the dealer because I'm within the 30 warranty, and I just want to be sure I know whats up.

Also, I have a distinctive front end noise - sounds like the front end only is driving over a steel grate bridge - but it only does it between 35 and 45 mph. The tires that were on it were not that good, fronts were cupped on the outside edge, so I put 4 new on but no change to the noise. I also thought it may have been the tranny but it shifts fine - and I also put it in neutral @ 45 and coasted down, still no change. Any help would be appreciated.

ok, they are talking about the downstream o2 sensor, i would try that, also o2 sensors might be covered under fords 100,000 miles emissions warrenty. As for the front end noise, try getting an alinment, otherwise jack up the front end and see if the wheels move up and down, or side to side. If they move both, probably front wheel beaing assembly, these are pretty pricey because they are fully sealed units, about 250 dollars per wheel beaing. Now if they only move up and down the ball joints are bad, and side to side probably tie rods. Now i think your front end is either a really bad wheel bearing, or a bad front hub. Start taking the front end apart and regrease the hubs and see if there seems to be a lot of metal shavings in there. Does your 4x4 work ok? If the hubs are bad, i would recomend putting in warn manual hubs conversion kit and you would never have to worry about them again.