Toyota Repair: 2002 Sienna stalls unless pedal is held, mass air flow sensor, mass air flow

Question
Mike, I have a 2002 Toyota Sienna minivan with the 24 valve V6 vvt-I 24 valve 4 cam engine. The van has 119k miles on it. When trying to start the van from cold it will only start if the gas pedal is depressed slightly and held. The engine will stay running until I let off the throttle then it shuts off emediately. I started looking under the hood for vaccume leaks but found none. The engine acts like the high idle is not kicking in, if I disconect the vacume line going from the throttle body to a little canister that regulates the position of the idle bump stop the van will start and idle and drive fine. Once it is warm it will idle too high though.

So this little vaccume operated canister seems to adjust for how far it allows the throttle mechanism to return. If it has vaccume it pulls in on the bump stop allowing the idle to drop very low and stall the engine. If it does not have vaccume (vaccume line unhooked) the bump stop will stay out far enough to keep the idle up to around 500 rpm. The van will run fine with the vaccume line connected once the van is warmed up, no stalling at all.

Should this little canister be gettinig vacume when the engine is cold? Am I looking at the correct thing here or is there most likely another problem? This little vaccume actuator is not mentioned in my haynes manual at all.

The vans check engine light is not on but it does put out 4 codes, P0110, P0100, P1705, I am not sure any of these relate to the stalling.

Any thoughts?

Thanks for any advice

-Rob Wallace

Answer
all the codes relate to the mass air flow sensor. You may have stored them when you took vac hoses off.
Leave the "crash pod" alone.

You probably need an IAC valve (idle air control0Its located under the throttle body.
Tap the throttle body LIGHTLY with a small hammer and see if it idles.
Once they gum up they should be replaced. Ive seen people try and clean them but Ive never hasd any luck.


Mike