My 2002 Ford Escape XLT (120k miles) chugs and sputters when started in wet and/or humid weather, and the check engine light flashes (sometimes goes solid and stays on for days later). In my non-mechanically inclined imagination, I would say that the sound and effect are as if there are air bubbles in the fuel line causing the engine to sputter when I step on the gas, however the problem continues even when I'm not accelerating. Also, the car shakes and trembles terribly when this is happening. This issue comes up when we've had rainstorms for a day or more, or when heavy humidity and fog roll in. Generally the engine begins to run more smoothly after a 30 - 90 minute drive, and the check engine light will go off a day or two later. I have changed the fuel filter, use premium gas, and have replaced the ACV valve once when the Ford dealer diagnosed an instance of the check engine light. I would be so grateful for any ideas - this issue is driving me nuts!