Have Toyota Questions? Ask a Mechanic for Answers ASAP
Hello and welcome
Thr problem in most cases like this is the idle air control valve, it may need to be cleaned or possibly replaced, since there are a lot of miles and considering the age of the vehicle I would recommend replacing it. To remove the IAC valve the throttle body has to be removed, the IAC valve is bolted to the bottom of the throttle body, remove the valve and inspect it for excessive carbon deposits that case it to stick, you may be able to clean it using a brush and some carbon dissolving liquid, after that make sure the movable part of the valve caqn be pushed open and returns to an almost closed position ( about 1mm gap) then re install it and put everything back together, if you can not clean the valve successfully just replace it, they are available from aftermarket sources.