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Discussion Starter · #1 ·
I have a lean code. It is a vacuum leak, it starts with 20 to 25% STFT lean after resetiing dtc. It completes all readyness settings to green however when driving. Light comes up while idling or braking.
When I squeeze the rubber hose from intake manifold to the Y tube connecting pvc and brake booster on top of the engine I hear somewhere a hissing sound and when measuring vacuum on intake manifold it reduces vacuum, but comes back when I keep the hose squeezed. I don't close it entirely off.The weird thing is that I cannot find any crack in the rubber hose part.

Also, when I press the brake pedal the vacuum reduces for a short period in time.

First: is it normal when squeezing this hose the vacuum should change?
Any clues where to look if this rubber hose by itself is intact?
 

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Sounds like it may be the hard plastic tube / hose that connects to the brake booster. It is hard to see because it is buried under a lot of other stuff, but if you look closely at the brake booster, you will see that a hard plastic tube / hose is connected to the reservoir. Feel along the hose closely, and chances are that you will discover that it is cracked where it attaches to the brake vacuum reservoir.
 

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There is a plastic vaccum line at the end of the run towards the booster. It's appearing to have a tendacy of breaking along the outside of the bend making it hard to visually see.

I ended up replacing ours last year with a pre-bent/reinforced rubber line. I do not recall the part number I used unfortunately.
 

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Discussion Starter · #4 ·
Vacuum leak

All thanks for the advice. I had a double leak. A small one in the valve to the air intake. This line is connected to the Y tube at intake monifold, the other end of the Y is connected to the brake booster. The plastic pipe was in a bad shape. So i repaired it by using vacuum re enforced rubber tube. I also glued the burned hole in the plastic valve. I will replace this one with a new one soon. My ltft is back where it should be and no cel anymore.
 
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