I am having a consistent popping from my exhaust. It happens when I let off after accelerating. A few factors have changed since it started happening. 1. I thought I was having some taping coming from the rockers on the drivers side so I tightened the rockers a quarter turn. The popping didn't start immediately after doing this. It started maybe couple hours after driving it since then. 2. The tapping seems to be an exhaust leak not the rockers. The leak from the header seems to be getting worse and I was wondering if this would be the most likely the problem. I also realize it could be the fuel. I did fill up about a half hour before the popping starting but it was Sunoco 94 octane and I've never had a problem with their fuel. Is there anything that might be more likely then others? Any input would be appreciated.