First look for broken or damaged vacuum lines. If all looks good you can spray carb cleaner on suspect areas with someone holding the idle at something steady and spray those areas. If there is a vacuum leak the engine will either run better or worse when you spray the leaking spot. Could be a hose, diaphragm, gasket etc., and if nothing found you move on to the other possiblilities of many possible problems. Use care and caution as carb cleaner is flammable and if over done on something hot can flash. Be ready for that and if that is unaccepable risk for you get some help as it can be done safely,
T
Tom Greenleaf - MetroWest Boston - USA
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