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post #1 of 4 (permalink) Old 07-08-10, 12:29 PM Thread Starter
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Vacuum leak and p0171/p0174 codes

I have read up somewhat on the common p1071/p0174 codes and what are common problems that make them show up. I know the pcv valve is one of the leading causes for it if its cracked.

I went to look at my parents expedition yesterday which has the 4.6. Started it up and started looking around for vaccum leaks to start. Immediatly I heard a wooshing noise coming from the back left side of the motor. I got some carb cleaner out and sprayed around some but couldn't find where the leak is.

Could this possibly be the intake manifold gasket?

Where are these PCV valves located? I think I saw one on one of the valve covers but it was in good condition.

The thing that got me about this leak is it seems like its fairly low on the motor, atleast low enough that stuff was in my way and I couldn't pin point it.

Any advice is appreciated, I come from the Jeep world so this is a lot different.

Thanks,
Jake

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post #2 of 4 (permalink) Old 07-08-10, 02:21 PM
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Re: Vacuum leak and p0171/p0174 codes

It could be the intake manifold in the lower rear center. There's a manufaturing hole that's plugged and it may be leaking there. It's definitly hard to get at to see for sure.

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post #3 of 4 (permalink) Old 07-09-10, 06:03 AM Thread Starter
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Re: Vacuum leak and p0171/p0174 codes

Quote:
Originally Posted by rtg143 View Post
It could be the intake manifold in the lower rear center. There's a manufaturing hole that's plugged and it may be leaking there. It's definitly hard to get at to see for sure.
Thanks for the reply. Is their anything else I should check in that area to see if it could be the culprit?

Also when you turn the engine off you can hear a whoosing noise from whever the leak is coming from for a few seconds after. Any specific type leak that would cause this?

thanks,
Jake
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post #4 of 4 (permalink) Old 07-09-10, 07:33 AM
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Re: Vacuum leak and p0171/p0174 codes

No specific leak. You just have to pin it down. Nothing I've seen is a normal occurance.

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