Have 98 Chevy truck. Truck turns over but will not fire. About a month ago I noticed that it would have a hard start and problem acceleration until it heated up when it got wet outside. Fuel pump was replaced about 4 months ago and you can hear it whine when you turn the key. Drove it home the other night no problem and then when I woke up, no go. Today it is dry but cold and engine will still not fire. I was low on gas (almost empty) so the first thing I did was add gasoline and like I said the fuel pump does engage but no fire. Truck has 120,000 miles and is nice and clean otherwise. V6 4.3L 262ci. Please reply with any suggestion. Thanks.