Vacuum Leak Causing Lean Fuel Mixture?

STEVEN46304

MEMBER
2006 FORD FOCUS
2.0L
4 CYL
FWD
AUTOMATIC
125,000 MILES

Our 2006 Ford Focus 2.0L has the Engine Light on. The only issue is that, at an idle, it runs rough, then dies. It will start right back up, but the problem is ongoing. A source said that it's possibly a vacuum leak. The source said that the most likely place for a vacuum leak is on the right front of the engine(while standing in front of the vehicle looking at the engine). Apparently, the PCV line has a 90 degree elbow in this area. There is a hissing sound coming from that area. My issue is that I'm not able to locate this elbow or the PCV line. I haven't been able to locate a vacuum diagram. Please help me.

8 Replies

HMAC300

MECHANIC
48,601 POSTS

Probably a broken piece on pcv or hose. This guide will help us fix it.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

Here is the PCV and vacuum line diagrams. Check out the diagrams (Below). Please let us know what happens.

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Saturday, June 21st, 2014 AT 6:07 AM

STEVEN46304

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2 POSTS

Using a can of carb cleaner, I've been able to pinpoint the leak to behind the drivers side of the intake manifold. There is a piece there that the parts store referred to as a vacuum switching valve. It's a small solenoid with 2 vacuum hoses on it. Replacing the hoses didn't fix the leak, so I'll replace the solenoid and let you know how it goes.

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Sunday, June 22nd, 2014 AT 5:32 AM

WDOMICHAEL

MEMBER
1 POST
2003 FORD FOCUS
150,000 MILES

Hi I am having a problem finding my vacum lines I think scan was poi171 bank 1 I can hear it but not sure where lines are is their a picture or better diagram I have a book for repair but can't seam to find a diagram. Oh for scan said running lean thank you

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Friday, August 21st, 2020 AT 12:45 PM (Merged)

WRENCHTECH

MECHANIC
20,757 POSTS

The diagrams will be in schematic form and won't even show the engine. Listen for the hissing and follow the noise to it's source. If you can't find it yourself you will have to get it smoke tested.

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Friday, August 21st, 2020 AT 12:45 PM (Merged)

RANDY SHARP

MEMBER
161 POSTS
2003 FORD FOCUS
2.3L
4 CYL
FWD
AUTOMATIC
88,000 MILES

Have been trying to nail down this problem this only happens when it idles have not found any vacuum leak yet. Day before yesterday did a compression check and it is excellent, but you know after I did that the engine idle's worst. Has anyone have a problem with a spark jump from the boot on a coil on plug, this is what I did I pulled one at a time like the old school way and two of the coils there was spark jumping because you know the spring that carries the fire is up in the boot and the other two you could pull them off and no spark jump, the plugs are not that. It don't seem like a vacuum leak miss it seems more ignition. Any other ideas I would appreciate it