Some of the pulls from the Northwest (from the Northwest Tractor Pulling Association website,
http://www.nwtpa.20m.com/pulling_schedule.html):
6/7/08 LEBANON, OR. 2:00 LEBANON STRAWBERRY FESTIVAL (O.T.P.A.)
6/21/08 BANKS, OR. 1:00 DIERICKX FARMS (N.W.T.P.A.)
6/22/08 BANKS, OR. 1:00 DIERICKX FARMS (N.W.T.P.A.)
7/25/08 HILLSBORO, OR. 7:00 WASHINGTON COUNTY FAIR
7/26/08 AMITY, OR. 11:00 ANNUAL PANCAKE BREAKFAST (O.T.P.A.)
7/27/08 AMITY, OR. 11:00 ANNUAL PANCAKE BREAKFAST (O.T.P.A.)
8/2/08 LEBANON, OR. 12:00 NORTHWEST TRACTOR PULLERS
8/3/08 LEBANON, OR. 12:00 NORTHWEST TRACTOR PULLERS
8/10/08 RICKREALL, OR. 12:00 POLK CTY FAIR (N.W.T.P.A.)
8/16/08 BANKS, OR 5:00 SUNSET PARK ASSN
8/17/08 BANKS, OR 1:00 SUNSET PARK ASSN
9/5/08 SUBLIMITY, OR. 7:00 SUBLIMITY HARVESTFEST
9/6/08 SUBLIMITY, OR. 6:00 SUBLIMITY HARVESTFEST
9/27/08 INDEPENDENCE, OR. 11:00 ANNUAL HOP AND HERITAGE FEST. (O.T.P.A.)
A lot to all of these pulls are tractor/gas truck/diesel truck combined pulls. I don't think there are any truck only pulls on this list. There are a couple of other associations that run some pulls in Washington, but I don't have info for them.