Ever since my last oil change and recall service to the brake pad sensors, I have been hearing a frequent double popping noise on the right side of my truck, seemingly favoring the front wheel area. This noise is impossible to forcibly repeat, however, like clockwork it always occurs twice (two double pops) on my way to and from work (and yes, the road is absolutely smooth, no bumps or pot holes to cause this). This typically occurs at around 60mpg and every 5-10 miles. Everyone I have talked to including the service department at my local GM have no clue what is going on. The truck will be going into the shop soon for troubleshooting. Any ideas what might be going on? Anyone with a similar issue?