Vacuum leak Yhe vacuum line manifold located just to the left of the power brake unit has what appears to be a broken off vacuum line. It is paired with another line and there is a plug on the manifold also. Where can I get a vacuum routing diagram? I can fix it but cant find a diagram

there can be several places which you can have vacuum leak.

1.intake manifold. it may get cracked to find it spray some brake pad cleaner on engine when idling. if its sound changes you can find the location of crack.
2.vacuum canister. it is plastic so it can be brittle in time.if it is replace it.(somewhere in car,plastic black cylinder) in most of cars near to front left fender.

3.vacuum lines ( small and rubber hoses which is used to operate hvac controls or cruise control on some designs).they are inside dash and behind hvac panel.you can cut them and fix them with adaptors.

4.brake master cylinder ( rare ocasions it can vacuum air if it is broken but you will notice when your brakes are not performing well)

In the engine compartment, locate black vacuum hose that runs from brake booster check valve to intake manifold, there will be a small vacuum hose attached to check valve at the power brake booster check valve. This is the vacuum line going to the heater control unit,check the hose all the way to the firewall, repair any leaks you find. And that should take care of your problem.......GOOD LUCK

It sounds to me like there is still a pretty good vacuum leak somewhere, and you should also check for any dis-connected or missing vacuum lines on the intake manifold, at the carburetor, and the large vacuum hose to the brake booster unit and the vacuum valve at the brake booster unit for any vacuum leaks or broken vacuum lines/hoses, and they can be hard to find because cracks in the vacuum hoses like to hide on the under-side of the vacuum lines/hoses especially the hard plastic ones. Also the carburetor could be loose or the carburetor base gasket could be damaged, the EGR valve gasket could be damaged, or the intake manifold gasket could be damaged, and these are all the most likely places to suspect a major vacuum leak.

Try cleaning the throttle body, check for vacuum leaks, check the fuel pressure.

vaccume leak or fuel problem

I had a 96 Chevy S-10. After an oil change it was running week and backfiring. took it to a mechanic that replaced the crank shaft position sensor, ECM module and the ignition module 3 times and still didnt fix the problem. Brought it to the dealership turned out it was a broken wire going to the ignition module causing all of that problem.

check for vacuum leak or bad iac valve

check for intake vacuum leaks.

Low / uneven idle problem can cause by a lot of components.

Dirty air filter

Dirty injectors + o-rings

Vacuum leak at intake manifold and vacuum hose.

Bad Idle Air Control Motor (IAC)

Low compression (170 psi + is OK)

Start cleaning and repair these trouble spots and see is there any improvement.

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For more advance DIY'er then you may try this.

Use a can of Berryman carburetor clean to locate the vacuum leak.


SEE SAMPLE PICTURE HERE


This is a 20-30 minutes job.

Vacuum leaks can occur in following locations.


Intake manifold AND/OR vacuum lines.


Intake manifold is not accessible unless the engine head if off.

You can still check the potential leak by spraying some Berryman near the intake manifold.

Listen for rpm increase after you introduce the Berryman (FUEL) at idle.


Do the same starting from the brake booster unit (the round unit) on the drive side fire all.

Carefully listen for increase of RPM right after to spray the Berryman to the potential vacuum spot.

Get a friend to HEAR the ROM increase or monitor for RPM on the tech.

DO NOT AIM the Berryman into any heat source.


PLEASE RATE my answer if it is useful to you.

Hi Monkeypaint!
I assume you have power brakes and I gather that it idles properly at times, but dies when the brakes are applied. This sound like a leaking power brake assist vacuum line or diaphram. You can verify this by locating the big vacuum hose connecting the intake manifold to the assist diaphram. This will be about an inch in diameter connected to the round item behind the brake master cylinder next to the firewall.

1. Disconnect the line at the intake manifold end, and plug the vacuum port on the manifold with a tapered rubber stopper or cap.
2. Being aware that you now do NOT have power assist to the brakes (requiring CONSIDERABLY more pedal pressure to stop!!!), see if the problem goes away. If it does, you have narrowed it down to the assist diaphram or the hose. If it still persists, it is an engine tuning/control issue, not related to brakes.
3. Do determine whether it is the vacuum hose or the cannister, remove the previously installed cap/plug, reinstall the hose to the intake manifold, disconnect it from the diaphram and plug/cap the hose at that end. Repeat step three... if the problem returns, the hose is leaking and should be replaced... If the problem still goes away, the Power Brake Assist Diaphram Cannister is leaking excessively and should be replaced.

• ***ALSO*** Any other vacuum lines leaking can lower the manifold vacuum to a threshold level where the load of power brake assist actuation crosses the line for adequate vacuum to idle*** So check all vacuum lines underhood, looking for a pronounced hissing at vacuum leaks. A manifold vacuum gauge is a relatively inexpensive diagnostic tool that could also be useful.

Well, hope this helps, and good luck! Don't forget to rate this answer!
Thanks!
-WB