I have an '88 4x4 p/u with the 22RE engine. When the a/c is on and I come to a stop, foot on the brake, the engine surges. As soon as I take my foot off the brake, the engine idles like its supposed to with the a/c on. I'm thinking since the engine idle up device that is activated when the a/c is turned on is activated by vaccuum, that there is a vacuum related problem in that system. Since the brake booster also works with engine vaccuum and the Engine only surges with the a/c on and brake applied at a stop that there is a bad component in the a/c idle up vacuum circuit, a vaccuum leak or maybe a bad diaphragm in the brake booster???????? Any one have any Ideas?????????????

 

Do what I did.

Unhook your brake booster and plug the vacumn line. See if the problem is still there.

If it is, your booster is bad.

Mine only does it when I really step on the pedal hard, but it does it enough I know I have to replace the booster.

 

Here is another thread from IH8MUD where some of us have a similar problem.

 

Mine did it and after a day at the toyota dealership all it was was a screw on top near the throttle body at the air filter tube needed to be screwwd in all the way. Some how it lossened up. At first we thought it was a booster but $30.00 later and feeling like an idiot it was just the screw had loosened up.

 

What screw exactly are you talking about? I know that there is the idle adjustment screw and the a/c idle adjustment screw(the big black screw with a spring around it located just off the intake manifold) is there another screw?

 

NO not the black plastic screw. It is directly on top where the air filter tube joins the throttle body. It's right on top and it set below flush when it screwed in. I wish I could do a picture I would show you. It is all metal. I am going to look it up in the manual I have and see if it has a name.

 

I think you are talking about the idle adjustment screw......I don't think that is the problem.

 

Its not listed as the idle adjustment in the manual. It is on top to the left near the clamp on the hose on the throttle body. In the manual it doesnt explain what the screw is. I wish I could copy the picture and post but cant. The picture is in a haynes manual I have and the screw is there. I will swing by the Toyota dealership where I was looking like a fool after the adjusment to see if he can help with the name of the screw.

 

ok, thanks....I appreciate it.

 

You talking about the screw that is on the left of the throttle body, about 13 mm in diameter. Pull it out and looks like a large needle valve.

I went and chenged my oil today and went looking at this today. In doing so, I found this screw to be loose too. I took it out, counting the turns and cleaned it up. Noticed the o-ring on it was quite flat and stiff and it is now planned on being replaced once I can get the correct o-ring. Doesn't take much of a turn on that screw to change your idle in a big way.

So does anyone know what this screw if for? It appears to control the air flow through the large hose under it. I didn't follow it today as I wanted to get in and out of the garage rather quickly this afternoon.