I have a 1998 Toyota Avalon XLs i changed the iac the rpm goes to one and stalls could it be the positon sensor that bad car will not stay on help

I second this method, works like a charm

It sounds like a classic case of an idle speed control motor sticking. If this problem happens when it is cold then does not do it until it sits and gets cold again this is probably the problem. The idle speed control motor is bolted to the bottom of the throttle body. Pay attention that throttle body needs to be removed to get it off.

Hope helps.

Pier_j Judging from what you have discribed. It would look at the fuel supply first . It sounds like its running out of gas check the fuel filter and then the pump for ampale out put you can but the line in a plastic bottle before the filter after its removed you should get 3 to 4 ounces of gas in about 5 seconds with key on. If it was a sensor problem you would have check engine on this is an OBD2 system so even if you don't have a reader you could take it to an auto parts store and they would read it for free . I know this must be frustreating but you need 3 things for the engine to run at all AIR INTAKE FUEL FROM THE PUMP AND SPARK AT THE PLUG TO FIRE IT I t sounds like you have most of it if you have no codes or lights on the dask check the fuel you might get out of this for under 10 dollars don't stsrt blindly replaceing sensors . Use a logical approch good luck with it

IDLE SPEED NEED TO READJUST .