Hi everyone,

I've got a '94 4Runner with the V6, 270,000km, and just about every time that I start it after it's been sitting for about 10 minutes or longer, it idles/drives rough for the first 15 or 20 seconds. After that, it runs great both while driving and idling. If it's only been off for a few minutes and I start it up again (like after getting gas) it runs fine, but if it's been off for about 10 minutes or longer and I start it up, it will idle rough and if I start driving it before the idle smooths out, it has a lack of power and the sound of the motor is not right for about 5 or 10 seconds, then it smooths out.

The gas mileage has not gotten any worse since this started, it's the same as it's always been. The check engine light is not on. It passed emissions testing a few months ago, though it didn't do as well as it did 2 years ago.

Someone I work with said that he's pretty certain it's the cold start valve. He showed me where it is on the motor, but what I'm wondering about is if there is any way to test it before I actually replace it?


Thanks,

Mark

 

The cold start circuit has a few components. One is the Cold Start Injector- sprays fuel into the intake when the engine is cold; and the other is the Cold Start Injector Time Switch- determines what 'cold' is and thus turns the Cold Start Injector on.
There's also the idle air control / auxillary air valve which let's air around the throttle, but ....

Check for voltage on the terminals for the connector to the Cold Start Injector with the engine warmed up. If you've got voltage on those terminals, the Cold Start Injector Time Switch is probably bad.