Vacuum Leak?

Redneck_ranger

Redneck_ranger

Banned
Here's the deal; my truck sounds like wind is blowing through the engine. No matter what, it always has an extremely loud whooshing noise, which gets louder as the RPM's go up. Once I hit 3500-4000, I can't hear my exhaust, my radio, or anybody talking... It's that loud. I have heard it's a vacuum leak by friends and people and mechanics, but nobody can find any leaks. Anybody know a cause of this?
 
ok im not shur bout the 4.0 but it sounds like what i had on my 3.0. check your EGR tube and hose line. you may need a new EGR sinsor.
 
Sounds like the booster hose or PCV hose has a breach. The PCV hose is known for it on the 4.0Ls.


If you cant smell the exhaust in the engine bay, it's probably not the EGR tube.
 
Okay, it would be awesome if you guys would tell me what those are. xD And where they're located. And no, I can't smell exhaust in it.
 
Wait... Would it show up on a code puller as a small emissions leak? I had my buddy turn that off way back in June and it never came back on after...
 
A vacuum leak that severe would typically trip a cell and give you one or both of these codes (P0171 and P0174, lean bank one and two) but it won't always. To look for vacuum leaks grab a can of ether and with the truck running spray a small amount at a time around the common vacuum leak sources like the base of the intake, PVC hoses, brake booster, egr flange ect and if the idle speed changes around any of those spots that indicates a vacuum leak. If you have one sever enough to hear from inside the cab you will find it quick with the ether trick. Does the truck idle ok?
 
kozal01 said:
A vacuum leak that severe would typically trip a cell and give you one or both of these codes (P0171 and P0174, lean bank one and two) but it won't always. To look for vacuum leaks grab a can of ether and with the truck running spray a small amount at a time around the common vacuum leak sources like the base of the intake, PVC hoses, brake booster, egr flange ect and if the idle speed changes around any of those spots that indicates a vacuum leak. If you have one sever enough to hear from inside the cab you will find it quick with the ether trick. Does the truck idle ok?
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It does have a small miss, and when you first start it up, it runs at about 1500 rpms for a few seconds. Oh, and I can feel vibrations inside the cab at idle.
 
Brake booster is on the driver side on the firewall. Check the hose going from that to the intake manifold (large rubber hose)
 
its kinda stupid and simple... but have you checked to make sure that your air filter box is connected and sealed tightly? i have seen that before where part of the box isn't in the notches or the notches are broken. also some after-market filters make lots of noise. other that that the most common vacuum leak is the pcv tube that runs around the back side of the engine. it collapses at the front passengers side at the elbow but the tube is all one piece.
 
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