Step on brakes, idle rises..

[DirtyComanche]

I want to say brake booster.

 

 

Anybody else?

[Pete M]

Check for a vacuum leak in the big line going to the booster.

[DirtyComanche]

Does that makes sense? I don't know how vacuum brakes work. But I'd assume if the feed line for it leaked, I'd have a high idle unless I was on the pedal? :dunno:

 

The line could use a hose clamp on the one end.

[offroader461]

I had a similar problem and when i stepped on my brakes the idle went up and i could hear a hissing...turned out the diaphram in my booster was torn(took it apart after)...my thoughts would be the booster is junk..my $.02

[mike]

i had the same problem, it was the booster, the diaphram inside it had split causing an air leak when i steped on the brake pedel, replaced the booster and it was fixed. you might also want to replace the vacum hose also, if it is like mine and has weather cracks it needs replced, hose is cheap compared to not having brakes and rearending someone because the hose gave out.

[DirtyComanche]

Okay, dead booster works for me.

 

 

I'll have to go get an E350 master and some random booster...