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Surging Idle When Brake is Pressed

1254 Views 7 Replies 3 Participants Last post by  SnowCindy
My idle only surges when the brake is pressed. I have been told it is because I moved from the South to Pennsylvania and that altitude difference can cause it. I was told to adjust the black screw that has the spring on it. Not the idle screw on the throttle body.

Any suggestions?
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first you need to find a different source for info,

It has nothing to do with altitude. you'd have to get a lot farther north for that.

It is because it is idling too fast. adjust the idle with the idle air bypass screw, it is the big flatblade screw on the top of the throttle. the black one with the spring is to adlust the A/C idle-up.

If you can not get the idle to come down to spec you'll need to find out why, and there could be several causes including but not limited to a sticking auxillary air valve, incorrectly adjusted throttle stop, ruptured diaphram in the
A/C idle up valve, etc....
OK...correct me if I am wrong but here is what I need to do.

Adjust the idle screw on top of the throttle to get it to stop surging. Once that is done, how do I get the A/C idle up valve set right because I have played with it a little.

The A/C idle up valve should be set so that the idle speed increases by 50rpm when the A/C is turned on.
I had the same problem. My high idle was intermittent, caused by a sticking dashpot. You may want to check that as a possible source.
Adjusted idle screw and reset A/C idle...everything on that end is great now.

Been a member of ToyotaNation for about a month now and I have to say this is great. Wish I would have found this site a long time ago.
The dashpot is located at the throttle linkage and prevents the throttle from slamming shut by slowly returning the throttle to the rest position. When it sticks, the throttle won't drop down to its proper idle. Some on the forum advocate removing the part entirely. All mine took was a good cleaning and lubrication. Glad you got your problem fixed.
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