Drove the truck around town today and drove her kinda hard... lots of popping going on. Then a cold front come in and has been raining and I had to go into town again this evening and since the dually was outside and wet already, I drove it. Didn't pop one time. I'm beside myself! TKingsbury, the sound is coming from the left front of the truck but I guess it could be something further back and the sound is traveling forward..... I'm going to give it one more go this weekend and try and find it. If I don't, I'm giving up. If I can't sell it whole, I'll part it out. What's a first gen engine worth with 103k miles??? :{