Apply brakes goes to floor engine idle chokes down let off goes back to normal,is thia avacumn leak problem,where to start to find?

It sounds as if you could use a master cylinder and booster replacement. The booster uses vacuum to boost pedal pressure and the choking down of the engine is cause from a vacuum leak. The soft pedal is caused by air in the system or loss of pressure in the main piston seal of the master cylinder.

There are a few obscure potential causes, but these are less likely than the most common reason: The power assist brakes are operated by a vacuum diaphragm which is provided vacuum from the engine. When the diagram inside the brake booster has a leak, when you apply the brakes it causes a vacuum leak for the engine which will raise the idle.

With the car in park, engine running, make sure that it comes and goes every time that the pedal is depressed and released. Another way to check it is to turn off the engine, wait about five seconds, then depress the brake pedal, counting how many times it can be pressed before the assist goes away (you will see a difference).

If you can press it four times or more, the leak may be elsewhere, however if it only presses once or twice (before it gets hard, and only goes halfway down), it has a leak and will need to be replaced.

Good Luck!

run a teat. Remove the vacuum line from the brake booster and plug off. Start engine and see if it idles normally. . Put your foot on the brake pedal and apply the brakes . If the idle is still normal replace the brake booster as there is an air leak in the diaphram.. The service light is probably recording misfiring and air fuel mixture problems.. run fault codes any way just to check it out .

Well it could be the booster but your symptoms don't really match it.
If the booster were leaking vac, the engine should be running faster than normal. And probably rough. And your effort to push on the pedal would be harder without the vac assist.
Usually when the pedal goes to the floor the system is out of fluid or the master cylinder is faulty.

Hi
This sounds like a cold start system fault, which is a number of things.

1. Cold start temperature sensor not operating correctly so the cold start system won't work when the engine is cold.
2. The idle needs to be set to the correct RPM of the engine when warm, if it is idling ok when it is warm then this wont be the problem.
3. Spark Plugs are worn and need replacing.

Most case's its the cold start system not operating correctly and if you have a good workshop to take it too they should pick this up quite quickly. Hope this helps, let me know how you get on.

replace the tps throtle possion sensor

Could also be a leak.

Have you checked the fluid?

Could possibly be the power brake booster also.

Bob

Vacuum leak at your brake booster ,have this check soon.

Hi,

Offhand, yes this would be normal. The high idle is brought about by the auto choke whose purpose is to hasten the reaching of operating temperature of the engine. The fact that the idle RPM goes down after some time is a good indicator, it tells us that the auto choke is working.

Just a start, do postback how things turned up or should you need additional information. Good luck and Thank you for using FixYa.

Thank you for allowing me to assist you, Before we do anyhing, I need some additional information.
Please respond to the following 5 questions so that I may be able to help you better.
Is you vehicle front disc/rear drum or front disc/rear disc?
When were the brakes changed last?
If so, front or rear?
If you apply the park brake, does the vehicle move at all when you put it in gear?
Finally, I am understanding that the brake pedal goes to the floor, you have no resistance on the pedal, and the vehicle does not stop when applying the brakes. Da?