The City of Cedar Park is suing a company that sold it a fire truck. The city says the vehicle is a lemon and has been trying to sell the truck online. The truck — a 2008 model Pierce Dash-2000 the city bought for $742,000 — was taken out of service by the city, according to a lawsuit filed last week against four companies that manufactured and sold the truck and the truck’s engine: Siddons Fire Apparatus, Inc., Siddons-Marton Emergency Group, Pierce Manufacturing, Inc., and Cummins, Inc.