sogabe

after going to the bank, all of sudden my car started running so weird.

I hear a big hissing sound from the engine, runs really rough, and brake became really hard so I'm assuming its a big time vacuum leak.

Funny thing is.. all my intake plenum, manifold(upper and lower) gasket is about 6months old, and the shop just gave me a call saying ALL THE HOSE ARE IN TACT IN GOOD SHAPE??!

so where else could this be coming from?
now they say they have to take out the plenum just to see where it's leaking from.. but I'm kinda afraid leak lies somewhere else..


could a vacuum leak happen from cracked head or something major like that??

any idea or input appreciated.. it's a 3.1L engine.

atomicskr

are you sure it isn't the brake booster line or the booster itself?

sogabe

does failure of booster itself cause shaky engine?

from outside I think there were no noticable crack or split in the booster itself,
but could inner failure of brake booster cause huge vacuum leak?

i think they already checked the fitting that goes to the booster, and it was okay.

Toehead

The brake booster has a LARGE rubber diaphram in it that can rupture. If this ruptures, there is a large vac leak. Easy way to tell, Disconnect the brake booster line and plug it with your finger and start the car... see if it runs better.

Also, the brakes should remain easy to push after the engine is off from the residual vacuum. If they are rock hard as soon as you shut the car off, I would suspect them first.

sogabe

ok it was the throttle body gasket.. now i gotta pay a ridclious amount for their diagnosis, and a piece of 5bux gasket.. shoulda looked myself