Vehicle acts up in cold weather. Code says cylinder 7 misfire. Ideas?

check or replace the ignition parts , wires , coil(s) weather and amount of fuel may have nothing to do with it

This sounds like it just needs a tune up and a good going over...P0307 - Cylinder 7 Misfire Detected...Possible causes;Faulty spark plug 7, Clogged or faulty fuel injector 7, Faulty ignition coil 7, Fuel injector 7 harness is open or shorted, Fuel injector 7 circuit poor electrical connection, Ignition coil 7 harness is open or shorted, Ignition coil 7 circuit poor electrical connection, Insufficient cylinder 7 compression, Incorrect fuel pressure, Intake air leak...The P0307 code means that the cylinder 7 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 7. If the problem persist more tests needs to be done to diagnose problem.