I have a 96 Honda accord 2.2L, since I had my exhaust replaced at Midas, not really what I wanted to do but, convenience took over. Since, then I have two problems that are driving me crazy and Midas can't fix.

1) the exhaust now make bellowing (vibrating/resonating) noise at idle, when in Drive and at idle.

2) every once in a while, not to often, the rpms cycle up and down between 1500 and 2000 RPM again at idle, until you rev the engine to 3000 rpm then it idle, then sometimes it goes away.

Are these related and what can I do to fix them?