I had a slow leak in my RF tire, 7 lbs/week which would set off the low pressure warning system. When the car was taken to the purchasing dealer, it was discovered that there WAS a small nail in the center of the tread, BUT, the tire could not be patched, as Ford apparently slathers a layer of white, flexible foam on the inside of the tread area. This material COULD NOT be removed by the dealer, either with solvent or grinding wheel. Tire was unable to be patched, NEW tire was $407. I opted to go for two Michelin AS tires for $257 each, and have a spare Continental for more emergency use. Now: OEM replacement tire does NOT have the white polymeric sound deadener! Be warned! Personally, I would PLUG the OEM tire myself!