My '89 Jetta GL has 100K miles and normally runs like new, but when New England weather goes below 20 degrees F, it "lurches" and "bucks" as if gas is not getting to the engine. (Fuel line freezing?) Anyone know what causes this and how to fix it? Engine is a 1.6L Gas engine. The lurching usually occurs when I accelerate and lasts most of the day even when the car is completely warmed up.