2001 Ford F-150

Tiny
STUART13
  • MEMBER
  • 2001 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 195,000 MILES
I have a 2001 F-150 super crew that has recently developed a vacuum leak. I have replaced all of the more evident lines other than the little lines to which I cannot find for resale The truck now has the sound of a moose in heat coming from the air cleaner and a check engine light code that says both banks are running lean plus under power it feels as if there is a misfire, would you advise me on where I should look for this leak as it is driving me absolutely nuts. Also when shifting into overdrive it jumps and shimmys
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Sunday, December 26th, 2010 AT 9:53 PM

4 Replies

Tiny
CJ MEDEVAC
  • EXPERT
I do not know much about your rig

My buddy's truck initiated the mating call to your rig, months ago

We thought it was several things, including bearings in all belt driven items (which he replaced. Just slingin' parts)

Using a 1/2 heater hose 3 feet long, one end crammed in your ear. The other end a "stethoscope"

Turns out the GASKET on his throttle body had turned into a "NEVER-ENDING KAZOO" ('cept vacuum was vibrating it)

He replaced the gasket. But this time he SPARINGLY used Silicone sealant to sorta glue it into place when it was sandwiched in place.

This Help?

The Medic
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Sunday, December 26th, 2010 AT 11:02 PM
Tiny
CJ MEDEVAC
  • EXPERT
I'd also try to do the vacuum stuff 1st---this may stop other issues you are having.

I have used Carb cleaner sprayed on "Suspect" lines, parts--listen for a "lull" in engine RPM when you hit the spot

But personally I like "STARTER FLUID" (it is flammable, and a blanket or FIRE EXTINGUISHER should be nearby!) I can hear Engine RPM INCREASE better than Decrease w/ cleaner. Around the throttle body is tricky (gets sucked in it and "teases" you!).I have found rubber devices near and right below it in the past. So check everywhere!

The Medic
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Sunday, December 26th, 2010 AT 11:14 PM
Tiny
ERNEST CLARK
  • EXPERT
Also, don't use silicon on any intake parts, as a very small amount sucked into the engine is enough to ruin your 02 sensors. Use a silicon free adhesive/gasket mating material.
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Monday, December 27th, 2010 AT 9:34 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Is this a 5.4L V8? As far as the smaller vacuum lines, are you refering to the hard plastic ones? If so, remove them and replace them with the standard type rubber hoses that will fit. If this is the 5.4L V8, behind the throttle body is a vacuum line that goes down then has a 90 degree bend in it. They are common to dryrot and cause major problems. However, your description says you feel air blowing from the air cleaner. The engine wouldn't run if the air cleaner was blowing out air, so check for another source for the air. Also, if it sounds like a moose, there has to be a large leak. That is what is setting the lean mixture on both banks (check engine light). Many people check for leaks the following way:

PLEASE NOTE: YOU MUST BE EXTREMELY CAREFUL WHEN DOING THIS!

Start the engine and spray carb cleaner or starting fluid lightly around the intake and all vacuum hoses. If there is a leak, the engine will rev-up when it sucks in the spray. At that point, you will know an aprox area where the leak is located to inspect.

NOTE: Both starting fluid and carb cleaner is extremely flamable. IF it hits an exhaust manifold or other component that is extremely hot or if there is a spark, it will catch fire. Make sure to have the proper type of fire extinguishier near you if and when you do this.

Let me know what you find.

Joe
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Tuesday, December 28th, 2010 AT 2:38 AM

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