What does the brake system have to do with idle speed or consista

Some cars have a vacume check valve on the vacume line that
activates the air duct to open and close . If the vacume is not right
it will not work properly . If the vacume check valve is ok then check
and make sure the heater core is not clogged up

Check the upper intake for vacum leaks, use a can of carb spray, if there is a leak then the engine will react when the carb spray gets sucked in the leak.

High idle is usually caused by a vacume leak. First place to check is the cold air intake manifold. All hoses, throttle body, and sensors. Throttle Position(TPS), Mass Airflow(MAS), Idle Air Control Motor (valve) IAC. Controls Idle speed

A malfunctioning throttle system can cause both a high idle as well as an engine stall.

A dirty air intake or cracked air intake tube is often the culprit.

How to Fix an Engine High Idle in Under 15 Minutes

what is the idle speed like at rest,and with air cond on?when pumping the brake pedal at rest is there any change in idle speed and quality?
Have you had the system scanned for any fault codes or live data check?
How well was the throttle body cleaned,I have had a few that had to be cleaned a second time internally.
I hope this helps or get back with your findings.

P0506 relates to the Idle air control system. The problem could be a dirty idle vale or the beginning of the motor failing. Try washing the motor out with some brake cleaner or solvent. Do this in a well ventilated area, be sure to reconnect it correctly. Hope this helps...

try this when your stopped apply your e brake release the brake pedal does the idle increase? push on the pedal idle get rough or lower? this usually points to a vacum leak check for loose or broken vacum hoses

YOUR PROBLEM COULD BE POWER BRAKE BOOSTER LEAKING OR THE NON RETURN VALVE. IDLE SPEED LOW.HAVE IDLE SPEED ADJUSTED.IT SHOULD BE 875 RPM.

There are two things i would check.First look for vacum leaks.Check all vacum lines,if you dont find any bad spots try spraying brake cleaner around intake manifold and listen for a increase in idle speed.The next thing to check would be the intake air sensor.This sensor tells the ecm what temperature the air is and richens the fuel mixture.

you got it . it is more than likely you have vacuum leak . to chek use a propane torch and while idling intoduce propane at possible area(intake gasket, egr valve , brake booster etc) if idle speeds up and smooth fix it.

Check for vacum at the brake booster. It sounds like the vacum line is broken or maybe you have a defective booster unit leaking vacum.