Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Fuel Systems Solutions, (NASDAQ: FSYS) were backfiring today, falling as much as 12%, and closing down 11% after reporting fourth-quarter earnings.

So what: The maker of natural gas engines and other alternative fuel systems turned a loss of $0.16 per share in the quarter, well short of estimates of a $0.04 profit. Meanwhile, revenue fell 5.5%, to $92.6 million, worse than the consensus at $96.4 million. CEO Mariano Costamagna noted "market challenges" in the quarter due to a decline in alternative-fuel incentive programs and a highly competitive European automotive aftermarket.

Now what: Fuel Systems' outlook for the current year wasn't any prettier. The company now sees sales of $340-$360 million, representing a decline of at least 10% from 2013, and a range well below the analyst consensus at $388.2 million. The guidance is based on assumptions including a slower global transportation market and the loss of a large customer. Despite the natural gas surplus at home, natural gas fuels have not caught on as some analysts expected. Shares of Fuel Systems hit a 52-week low today, and peers like Clean Energy Fuels and Westport Innovations continue to struggle, as well. As today's outlook makes clear, Fuel Systems' won't be turning the corner anytime soon.