Honda Accord Idle Problem
 

I have a very high milage 92 honda accord. This past summer i started having a problem.
The car starts, idles fine and drives fine. After it warms up though it idles very rough and the hotter the day time temp. the worse it idles. It also smells bad when I park and turn off engine. It does not idle near as rough on a cool days or not rough at all.
Also now the car at idle (when warmed up) has pulsating rpm's. Idles high and low, high and low but goes away if I put in gear or turn on air cond.
Looked in a repair book could be a variety of things. I can't find a vacuum leak that I can readily see. Got any ideas where to start.

welcome to the forum. Check your egr vlv. this is tied in with your exhaust sys. gets a lot of carbon.

clean out you IACV or idle air control valve a dirty iacv will cause erratic idling.