Another Vacuum Leak or What?

[ben416]

I have been noticing a loss of power in my 2001 Ranger 4.0 over the last few weeks. I had also been hearing a buzzing noise on and off which I thought sounded like electrical buzzing from around my coil pack but it turns out it was the hose under it. When I wiggled it, the noise went away on and off as I moved it. The noise also fades out like vacuum when you shut off the engine after the revs drop to 0. However I also noticed a hissing coming from under the plastic throttle body cover recently too. I'm assuming either spot could be the cause of my power loss. I can't even spin the tires easily in dirt in 2nd gear and the A/C / Defroster kills my power even worse.

I'm going to a friends house with a garage tomorrow to look into the hissing noise under the plastic cover. I assume that may just be a loose hose. However the leak causing the buzzing noise puzzles me. I'm not sure what the hose goes to or even what part I would need to replace. It goes behind the engine and I think maybe around to the intake on the front.

Here is a picture of the L shaped joint the hose is connected to that the buzzing is coming from. It seems to be a little lose from the engine.



Any ideas on what this is would be appreciated. I tried looking up vacuum diagrams but I couldn't relate them to my problem as I can't see where they match up to my engine bay.

Thanks

Edit: FYI plugs have been changed, air filter is OK and the MAF has been cleaned recently.

 

[ben416]

Well after picking through the Haynes manual I found a picture that looks similar and I think its the PCV valve. I'm probably just going to replace it since the buzzing noise is coming from there. I'm also figuring the hissing from the throttle body area will just be a loose vacuum line.

Let me know if ya think I'm missing something. Thanks

Edit: Just got the P0171 lean bank 1 code.

 

[comparini3000]

i just recently fixed the same code on my truck. All the research i did pointed to a vacuum leak.

i couldn't find one so i replaced my PCV valve and fuel filter, which kept the code away for a while but it came on again. i searched for any leaks again and found one in the hoses coming out just below and to the passenger side of the throttle body, right at the bend of one of the hoses.

maybe that's where your leak is too

 

[ben416]

i just recently fixed the same code on my truck. All the research i did pointed to a vacuum leak.

i couldn't find one so i replaced my PCV valve and fuel filter, which kept the code away for a while but it came on again. i searched for any leaks again and found one in the hoses coming out just below and to the passenger side of the throttle body, right at the bend of one of the hoses.

maybe that's where your leak is too

Funny you mention that because that's exactly what it ended up being. It was a L shaped rubber hose connecting 2 metal tubes. Napa didn't have a replacement but gave me some radiator hose that worked just fine. No more CEL and the truck runs normal again. I'm just glad it wasn't the intake seal.

Thanks for the tip. Merry Christmas!

 

[Ranger44]

That buzzing noise is actually a common enough problem that Ford put a TSB out for it. It's supposed to be the bolts that hold the coil pack bracket down aren't tight enough. They are to be turned an additional 45*. Supposed to cover ALL OHC 4.0's.

 

[ben416]

That buzzing noise is actually a common enough problem that Ford put a TSB out for it. It's supposed to be the bolts that hold the coil pack bracket down aren't tight enough. They are to be turned an additional 45*. Supposed to cover ALL OHC 4.0's.

Thanks a bunch! I'll check that out too just to make sure they are in good. It probably went away temporarily when things got moved around fixing the other issue so I haven't noticed it come back yet.

 

[comparini3000]

Funny you mention that because that's exactly what it ended up being. It was a L shaped rubber hose connecting 2 metal tubes. Napa didn't have a replacement but gave me some radiator hose that worked just fine. No more CEL and the truck runs normal again. I'm just glad it wasn't the intake seal.

Thanks for the tip. Merry Christmas!

no problem, glad it was a simple fix! Sounds like you were smarter than me though....i went to the stealership to get the "right" replacement hose. $40 for a simple chunk of rubber

i'm just a little late, but Merry Christmas!