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Jul 20, 2014 | 12:57 PM

jawdoc

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hissing

over the last few months I have gotten a loud hissing sound coming from the pasenger side. It is RPM dependant.

Im also having a hard time going up hills, although the trans shifts fine and the fluid level is good.
any thoughts?

2008 F250 V10 Lariat, 124K

Jul 21, 2014 | 05:00 PM

krewat

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Joined: Jul 2002

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From: Long Island USA

Broken exhaust manifold studs? If it's sucking air in, and yes, it can actually suck air into the exhaust under load, it'll throw the air-fuel ratio off according to the O2 sensor, and run way rich to make up for the extra oxygen.

Jul 21, 2014 | 05:47 PM

DSN46

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From: North Florida

Vacuum leak will indeed cause the hissing... I have had one before... not exhaust manifold though. I also lost some power with the leak.

Good luck tracking it down and let us know what you find.

James

Jul 22, 2014 | 01:48 PM

krewat

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From: Long Island USA

Duh, don't know why I didn't think vacuum leak, good call DSN46

Jul 22, 2014 | 05:45 PM

DSN46

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Joined: May 2003

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From: North Florida

Quote:

Originally Posted by Krewat

Duh, don't know why I didn't think vacuum leak, good call DSN46

Thanks Krewat!

I just read my post again and I absolutely was not suggesting that it could not be the exhaust manifold (cause it very well could be).... I was just saying that the manifold was not the problem in my particular case.