Ok you diagnose this one

[drtbiker]

I would like to start off by saying i have a surging idle problem. This is what i came up with the car continues to surge 800 to 1100. But get this i pump the brakes alot until the brakes get really hard and the car idles perfect at 600-700rpms in the range. But i give it a while and let the brakes get soft again and there goes the surging again.

Can the brake booster affect this?
Is it a vaccum leak?
When the car's idle doesnt surge it runs good.
When the car has a surging idle problem it doesnt run as hard.
The weirdest part of it all is when i pump the brakes until they get really hard the a/f gauge gets readings when it is soft and surging the o2's read rich.....


Is it a bad brake booster?

Sometimes the brakes get really really soft when driving i can almost push it to the floor.


thanks
sorry about the length of the post