I,ve got a 2000 Jeep Grand Cherokee, the engine occasionally will surge 200-300 rpm while at idle. Sometimes its fine, and then the next time I get into the jeep it will do it. Any ideas or help would be grateful. Thanks

Any codes? It can be a vacuum leak, the IAC motor and a few other things.

No codes. It runs fine the RPM's just shoot up 200 to 300 for about 5 seconds and then drops back to normal. Then sometimes its fine and runs smooth.