They weren't faring so well in that market.
2005
Low sales.
2003
Around 1984-1985 timeframe
In 2003, Ford introduced the 6.0-liter Power Stroke that replaced the 7.3-liter version.
The 2005 Ford Thunderbird was the last model year
2011
Mainly due to overall lagging sales in the compact/mid-size pickup market. Same reason Ford and GM eventually dropped their compact trucks as well.
1997 was the last model year that you could get the 460 ( 7.5 liter ) in the Ford F-250
Chevrolet never made the Cheyenne trucks for public distribution. The Chevrolet Cheyenne was only a concept car made for future models.
G.M. and Chrysler management probably wish that Ford would =)
2010 was the last model year for the Ford Explorer Sport Trac