Having an idle problem only when vehicle is in gear. Vehicle runs great except for expected knock at 190K... When I come to a stop it wants to die. If I sit in a parking lot put it in drive with my foot on the brake, eventually usually 15-30 seconds the idle will drop from normal 750-850 rpm to 500 or less all of a sudden and struggle to run, sometimes it will stay running, other times will die.

I bought a new idle control valve after searching similar symptoms, had it installed after looking at what a bitch it was going to be, still have the problem. Like I said the engine runs great except for when I stop at an intersection, ect.

Any ideas on where to go next? Recently replaced timing belt and had the cam timing checked, I replaced plugs and wires.

Is there anything with the transaxle that could be locking up causing the sudden decrease in idle? Vehicle shakes like crazy when it gets to 500rpm or less.