I've been having this weird pop like backfire whenever I let off the gas after going for a while on a straight road like the freeway or anything like that. It really does it if I'm driving with the OD off. I'm not sure if its a big deal thought I'd see if anyone has any ideas. I have a 2001 Dak R/T, with a stock exhaust I believe. I bought it used, but it looks stock.