The best way to check for a stopped up exhaust/catalytic converter, or
any other exhaust restriction. Is to put a vacuum gauge on your engine and
run the RPM'S up to about 2000 RPM'S. If the exhaust has any restriction at
all, the gauge will go from reading vacuum to reading  pressure as the RPM'S
go up.

Howard

> I vote plugged up catalytic convertor.Does it overheat too,or get hotter
> than normal? A plugged cat can sometimes be checked by looking at the
> exhaust. In a normal engine the exhaust is strong and in "puffs". A
plugged
> convertor, in addition to the above symptoms,can show a smoldering,weak,
> exhaust without the puffs.Also a lack of power.
>