My 93 liberty wagon has a loud ticking or fluttering sound under load, it ticks in time with the exhaust system and can only hear it with acceleration & underload. Cant hear it when idleing or low revs ,making me think its a manifold gasket. Ive checked for leaks, there are none but its still there.
Any thoughts? Been bugging me for ages, can only hear when the windows are down and its loudest in a tight street or when theres something for the sound to bounce off.

ANY HELP APPRECIATED!