You could have a clog in the intake or exhaust. Sometimes the catalytic converters fail and fall in on themsleves. You can do a quick check, this is not fir sure it is bad, by smacking ti with a rubber amllet or your hand and listening for loosee material. Remember you have more than one in some applications.
A large vacuum leak would also cause this behaviour and it should be something you can hear with the engine running and the hood open.
Thursday, July 12th, 2012 AT 8:06 PM