Lean when pumping brakes?

[solo.]

Well I just typed up a long post about this and the server acted stupid, so I lost it.

Anyways, here's the short version.
-drove today with wideband 02 hooked up, since the past month
-noticed while at a dead stop that constant pumping of the brakes causes the car to run lean(all the way up to 21!!)
-once their is constant pressure or when I let go of the brake, the A/F ratio goes back to 14.7 (which is normal)


So, any reason to this?

Sorry if I'm an idiot for not searching in advance.(bow)

[solo.]

Any clue?
I've tried opening the windows (which draws A LOT of power) while idle and the A/F ratio stays the same.

This only happens when I pump the brakes on and off constantly.

[TheMAN]

leaking brake booster possibly

[peajay]

It's about vacuum not elecricity...pumping brakes uses vaccum from your engine, at a certain point it cant keep up and basically causes a vacuum leak, which causes you to lean out. you may want a bigger vacuum resivoir, if your brakes dont feel weird at all i wouldnt image your booster is leaking.
maybe just dont sit there and pump your brakes for no reason?

[solo.]

Of course I don't pump my brakes for no reason while idling. I was just curious..lol

So I guess nobody has a wideband hooked up that can check?

[peajay]

It's normal.....My car will go to the 19's
read my previous post, everyones car will do it.

[Gasological]

How about when starting the car, the brakes are rock hard? Mine's only started doing this since it popped the coldpipe off the TB three weeks ago.