problem with corolla 2003

[ersa]

hi guys,

i have a little problem with the toyota corolla 2003 and is that when im running and press the brake the rpm drop down to 600 and the vehicule vibrates, the mechanic has cleaned the throttle body and the filters, cleaned the iac valve, new spark plugs, and the problem persists.

the iac valve was cleaned without disconnecting the connector, we disconnected it and the car improved but the rpm still drop

when im in reverse normally the rpm drop more, we resetted the ecu and the problem improved some days but the problem came back.

in the only occasion that the car improved was when we disconnected the iac valve and the screws and there it improved some days but still the same thing but less intense.

also i notice when im stopped in the vehicule the rpms increase a little, mechanic checked and no leaking, the mechanic also cleaned inyectors, checked coils, changed filters.

I have noticed as well that when i accelerate it fast the car it pulls a little bit and when you go in U turn i feel the car heavy.

what could be the problem, replacing the iac valve??????

[gingn]

what size and kind of socket did u use to get the iacv bolts out?

[invader]

If you're still on the original intake manifold black gasket, it's most likely leaking and causing your problems. Toyota's revised orange gasket is under $10.

[mikered30]

Which engine is this?

[flash2563]

the engine is 1zz-fe, but the gasket manifold is good i believe because dont have the code p0171 dont have check engine on...

[invader]

Your original intake manifold gasket is leaking. Replace it with the new Toyota revised one.

[ersa]

could it be the iac valve, i have ordered a new throttle to see if it is that what do you guys think???

because is not giving me any error code so i am assuming its the throttle issue, your oppiniions please would be most appreciated

[johnoh]

Yes it could be the iac valve and cleaning it is as good as replacing it. Since it happens when you hit the brake, check for a vacuum leak like the intake manifold gasket. Don't assume that the check engine codes will necessarily point to the issue.