Every now and then my car has a tendency to stall at idle. The idle will surge up to 1,000 rpm and then drop to about 500 and then sometimes it soes back up then either repeats the process or stalls. The exhaust smells rich if I give it gas to keep it running. My car has 94k miles on it. It appears to have the stock plug wires and possibly the plugs which I have not checked. I cleaned the IAC motor, the MAF, and ran some seafoam through the intake and in the fuel system. My K&N filter was extremely gunked up when I bought the car so I cleaned that along with the MAF. Any ideas? Some times the car runs fine and other times it just wont hold an idle..