 This is a limited-time offer, so log on to 100radioshows.com. That's 100radioshows.com. At Hot Shot Secret, we share the science behind common diesel problems. For example, stiction. Engine oil can break down under extreme heat, leaving behind varnish, a carbon-based deposit that creates drag on the engine's moving parts. This sticky friction is stiction. Symptoms include a rough idle and the loss of fuel economy and performance.