Ok, I've cleaned out the IAC and replaced the TSP sensor but my 2000 4.0 auto is still doing weird things at half a tank of gas. It rev's up about 400-500 RPM's over the idle. It does it in park and in drive but only at about a half of a tank. No vaccum leaks that I can find. I thought maybe it was the ingenuis internal fuel filter system but numerous folks have said that wouldn't cause that. I've spent $$ on fuel system cleaners too. Anyone have any clues? Any prior posts regarding these issues? Am I alone in the world?