Weird Idle Problems, brake causing higher & lower rev?!?!, Need some brainiac help please!!! Options

[jhaletama]

Hi guys,

Just had the head rebuilt on my 3sfe 1997 ST202 celica.

After being put back together couple weird problems.

1. If the car is started and just left to idle no problems, when you push the brake down it lowers the revs and as soon as you release the revs go up?! air con is off.

2. Once the car is warm and you drive it when coming to a stop the car wants to stall and die. air con is off.

3. when you drive the car at cold runs like a dream. once warm the above problems start. air con is off.

4. Car Temp gauge always sits about half way has done since i bought the car but lift the bonnet and you can feel the engine heat! it runs pretty hot. is this normal?

now the only thing i changed which is not from this engine is that black air valve on the top left side of the intake manifold. i accidently snapped the plastic tip so just grabbed another from a toyota camry. don't know if this will have anything to do with it or not.

when head was built, new gaskets from block up, new spark plugs, filters, oil, anti freeze.

any help would be greatly appreciated!!! Thanks again.

[blu94gt]

no, no oil.

repeatedly pumping the brakes can raise your idle, thats normal. but hitting them once and that raises the idle alot while they're held is not normal. the power steering should raise the idle, thats normal.

no oil?

If you pull the vacuum line, there should be no oil (if there's oil, then your brake booster is bad).

The brake booster has a vacuum line running to it from the intake. Vacuum from the engine helps move the brake master cylinder: this is how your power brakes work.

Now what I think is wrong is that
1. your brake booster has a leak in it, causing your engine to lose vacuum, or
2. most likely the check valve in your brake booster line is broken, which allows the vacuum pressure to leak, causing your problems.