My issue is with my exhaust. If I leave my driverside window open I get a lot of exhaust odor in the passenger compartment. This only happens when I get on it. The motor runs fine, I can't hear any exhaust leak, and I inspected the pipes from the "Y" pipe back to the exhaust tips. Everything from the catback is new. I also am having "popping" during deceleration, no matter the temperature of the engine. I haven't checked the manifolds because I've replaced the gaskets not all that long ago and I usually would hear the tic-tic-tic if it were a leak there. I've put a wrench on all the bolts to the "Y" pipe, and cat. All were tight. Where would the leak be coming from where I can't hear it? This is a stock 5.0 L69 with a recent rebuild on a ccc carb. New ERG, PVC, just about all of my emission components are new.