97 caravan 3l. int. rough idle.

I have a 97 Caravan with a problem that is driving me nuts.I have over 200,000 miles.original tranny and well maintained.Van drives like new then occasionally it starts idleing rough until it cuts out.In a couple of hrs. its back to normal.I changed plugs ,wires ,dist cap, rotor,pcv valve,egr valve,crank sensor.Throttle body was disassembled and clean with new gasket.There are no codes.One thing I noticed is when if does it there is a rushing air noise coming from the throttle body area.PLEASE HELP.:banghead:

That's cool you have over 200K on your van. I just got my 3L van last year and it has 85K. If you hear air when it's idling bad it sounds like a vacuum leak. Best way to find it is when it's acting up. Get some carb spray and spray around the intake and other places air can get to. You can also take some needle nose pliers and momentarily sqeeze vacuum hoses to make sure wherever they're going isn't leaking. Try the vacuum break booster hose...the one going inside to the heater controls...the fuel pressure regulator...etc. hope you find it. do you have the 3 speed tranny or 4? did you adjust the bands?

Thanks for the tip.I did check for vacume leaks.The noise sounded like the air in the throttle body when the engine is revved.
I think I may have found the problem, time will tell.When I installed the new crank sensor, the gap was too big, I reinstalled it to the correct gap and so far so good.My trans is 3 speed.Changed fluid 4 times,no band ajustments.I have minor probs.clunks in reverse when cold,also hesitates from 2nd to 3rd
when cold, ok when warmed up.