1994 Disco 1, 3.8 V8, 5 sp. Manual. High mileage vehicle. (173,000) Engine starts up from cold great, idles at about 750rpm. Has plenty of power, engine smooth, .....but after engine warms up when coming to a stop sign, and engine drops down to idle..now about 1000 rpm (clutch pushed in, foot brake applied) it will start to produce stuttering sounds (a kind of a rattling) thru exhaust. When I start to accellerate after a second or two the stuttering will stop. I am running premium with a can of seafoam added to gas. I have changed plugs and wires, new air filter, cleaned throttle plate (Butterfly area)..made sure all vacuum connections are secure. I am really at a loss as to what to do. Please note, this is a sound that comes "only" from exhaust, the engine does not have any mechanical sounds at all other than the whirring of normal operation...no ticking or anything.

 

After you drive it and the exhaust is hot park it, crawl underneath with a hammer and GENTLY tap on the catalitic converters, if they rattle it means that you need new cats because the baffles are falling apart. It's common so dont worry.