stumbles while braking

[themadness]

94 3100

it started stumbling the day before yesterday when ever i am on the brake at stoplights or signs. if i put it in park it pulls back up and levels out. it doesnt do it all the time. and only when i am braking. the oil pressure gauges drops a little when it does it. any ideas?

**i know i ask lots of questions fellas but its the only way i learn........it helps interpret the codes and symptoms i run into. thanks for being patient.***

[DTMAce]

Vacuum leak.

May need someone to help you, by pressing on the brake and you listen for the hissing. I would check the hose from the booster to the intake, make sure its tight and in good shape. Also check the bellows of the booster, Chad last fest had punctured a hole in his, we had to bypass the booster so his engine would run right.

[themadness]

a quick visual check of the vac line and it seems to be good. i guess i will go over it again tomorrow and check it thoroughly. what exactly are the bellows?(told ya i'm a noob)

where else would vac leaks be? a pcv valve change as well?

[DTMAce]

Sure they can be other places, but if you hit the brakes and it does it.....
Only thing you can do is examine all your vacuum lines, make sure none are loose or dry-rotted, etc.

Might try unhooking the booster's line, plugging it and see if that cures it. Easy enough as a test. If so, your leak is in the booster itself. Keep in mind, if you do this, the brakes will be damn hard to press without the booster, so be careful if you actually try to drive it that way.

[themadness]

update:

started it up this morning and idle is rough and now i have water come from the tailpipe

i got gas from a place i dont normally use.....bad gas?

hell i dont know anymore

[DTMAce]

How much water? Cold days will always give you a bit of water, that is normal.

[woody90gtz]

If it's ok in Park then it's not a brake booster vacuum issue...it's just an issue with the lower RPM on the brakes in Drive, making the issue more noticeable - whatever it is. In my experiences a vacuum leak will make the engine idle high, not low.

[themadness]

How much water? Cold days will always give you a bit of water, that is normal.

about 2 second drips........also drips from the front of the muffler

[DTMAce]

Once the engine is warmed up that should slow then cease, unless its pretty cold out. Condensation in the exhaust during colder weather is normal. It doesn't typically mean you have water in your fuel, but yes its always a possibility. Good news is, if there IS water in the fuel, you will be rid of it pretty quick, as water will settle to the bottom of the tank where the pump will pick it up, so it should clear out fairly quickly. You can also throw in a can of dry gas or something too. Won't hurt.

If it's ok in Park then it's not a brake booster vacuum issue...it's just an issue with the lower RPM on the brakes in Drive, making the issue more noticeable - whatever it is. In my experiences a vacuum leak will make the engine idle high, not low.

Yeah, but if he is in park, he isn't using the brakes either... lol

Although you can pump your brakes while in park, see if the same condition results. Hell I don't know. I agree that normally the idle will jump up, but for me it was the only thing that made sense, unless his car is under a large electrical load when the brakes are applied for some reason.