[H. L. Chauvin]

"If" an intake manifold leak was "the" problem, the test specified in message #13 would have indicated some plugs were "dry".

Again lack of fuel where it really counts, i.e. at the end of the line where one needs both "spark" & "fuel", "inside" the combustion chamber.

Engine overheating at slower rpms at traffic lights could warrant a slipping fan belt or radiator cleaning attention.