Elvota

When I start up to drive my 4Runner on these "cold" AZ mornings, I get a strange sound inside the cab.

It sounds like a vacuum leak. Thing is, if I apply the brakes even the slightest... it stops completely. Once everything is warmed up, no more "hooosh".

I don't seem to have any performance problems with either the motor of brakes. The 4Runner has done this for some time, but I always forget about it when the seasons change and the colder temps go away.

Any guesses as to the source?