Truck owners are going after General Motors. The company is being accused of allegedly designing a diesel engine that can cheat on emissions testing.

General Motors became the third automaker in the last two years to be accused of installing software on diesel vehicles that allowed them to beat U.S. emissions law.

The civil lawsuit was filed on Thursday and claims the diesel versions of the Chevrolet Silverado and GMA Sierra pickups produce higher levels of nitrous oxide when they are being driven than during tests.

This comes just 2 days after the U.S. Department of Justice sued Fiat Chrysler on behalf of the EPA alleging that some of its Ram diesel pickup trucks cheat on pollution tests. Fiat has denied any wrongdoing.

The lawsuit demands a jury trial and seeks restitution. GM shares fell 85 cents in afternoon trading Thursday

General Motors is fighting back saying that these claims are “baseless and we will vigorously defend ourselves.”