89 XJ RENIX low rough idle

My 89 XJ started having a low idle a couple weeks ago. It starts up fine, to 1100-1200 rpm drops down to 500 rpm, idles rough. In drive slows down more, turn AC on goes down to 3/400 and wants to die. Tried cleaning IAC, and cleaned TB, helped a little, replaced with 2 other IAC's no help. Pull a vacuum line instantly gains couple hundred RPM. Replaced TPS and adjusted, no change. Pull vacuum line to MAP dies instantly. Off idle runs great w AC. Platinum plugs, new sp wires in last year. Definitely NOT EGR. - don't ask, Free flow 2 1/2 in exhaust, cone air cleaner, mopar cam. I've been driving my MB diesel the last month and a half as I just bought and it gets a lot higher MPG and burns Veg oil! Searched and read 9 pages of low idle, but...