If you called me out for a service call on it...I would change ALL fuel filters and screen strainers if so equipped...insure that low points in supply lines have no ice ....fill with clean fresh WINTER fuel...prime and bleed per mfr's procedure. If it doesn't clear up and run well within a few minutes...you could have many other things wrong, one of the most likely would be an injector stuck open allowing compression pressure to backflow into the fuel system flooding it with high pressure air. You will have a 100% miss on that cylinder so it's easy to find by cracking the hi pressure line one at a time or just feeling the individual exh outlets if so equipped.
