Our Ask Tony and Tucker question comes from Jerry Tarasek in DunnLoring, Va. Jerry says, "Sometimes during my drive into work on cold mornings I notice a liquid dripping from the tailpipe of the vehicle in front of me. Is this condensate or spent fuel? Is there a certain weather condition that will cause this phenomenon, such as air temperature, humidity or dewpoint? Does it only occur in the winter or can it also occur in the summer?"