One person is facing federal charges for allegedly attempting to light Molotov cocktails to start a fire at a Loveland Tesla dealership in February.

Winter grade #2 fuel begins to gel at 10- to 20° F ... has a set of High Frequency Reciprocating Test Rig (HFRR) standards for diesel fuel additives, but testing is voluntary.

But the smoke test means something else for cars, especially those powered by diesel fuel. And passing diesel exhaust tests can become something of a chore. To make passing these tests a little ...