[Hinch45]

2000 Jeep TJ with 116,000 miles
As we all know if it’s not one thing it’s another. Anyway, I started my Jeep up a few weeks ago, started driving and got about 2-3 miles before I heard a strange whistling sound. Pulled over and noticed that the whistling sound is only when I am off the gas pedal. As I got on the highway I noticed it got louder the faster I went, but again only when I take my foot off the pedal. From time to time the whistle will stop on its own sometimes not.

After doing a little bit of research around various sites, I cleaned the throttle body as best I could without removing it. With no garage and the cold weather I am limited as to what I can do right now. I tried tightening the intake manifold which was another suggestion. I checked all the intake hoses and PVC valves on the crankcase. I tried playing with the air filter box, I have tried everything and cannot find where this is coming from and it’s really starting to drive me nuts. When I get out of my jeep and open the hood it can be a piercing sound. Has anyone experienced this before?

Again I only hear it when I take my foot off the gas pedal and sometimes it will go away, mostly when I come to a stop at a light or something. And it definitely seems to get louder the faster I go and then let off the gas.

Any Suggestions?

Hinch

 

[Jeeps4sale]

Exhaust leak? What motor?

 

[Hinch45]

6 cylinder automatic

 

[yjkid95]

Like a screeching sound? Is it steady or is it high then low then high then low etc.

 

[wavebacktothetj]

does it sound like a tea kettle? if so I know exactly what you are talking about mine did this a couple of years ago during the winter when I would take my foot off the gas after driving around for a minute or two, I messed around with the iac valve filter box throttle body and disconnected all the rubber hoses and reconnected them and still nothing after a while it just goes away it's extremely annoying, it's a vacuum leak of some sort it did that for that one winter once warmer weather came through it stopped and never came back

 

[burton160w]

Have a shop run fog through your vacuum lines to find the leak. That is exactly the problem.

 

[Neil F.]

x3. 6 cyl auto. This is the third winter I have had the Jeep (I swear it did not do it the first winter) Last year, same as you discribe. It is off the gas or very light throttle when it occurs. It does not do it all the time and so far it is not as loud this winter or as much. Mine doe shave a TB spacer from the PO (I know it's useless). From posts I know they cause whistling and thought it might me the cause but just have not removed it.

 

[Hinch45]

Yes it sounds just like a tea kettle and started when it got cold out. It doesn't begin right away which i thought was strange, usually begins around 150 engine temp. It screams when I let me foot off the gas on the highway. No loss of power or rough idle just a insanely annoying noise. I cant stop until i fix it for find out whats causing it.

ugh!

 

[KMJ]

2000 TJ 101,000 miles
I've had the piercing whine at idle and constant throttle problem for about a month. Tonight I visited a friend with all the right tools and checked all the manifold bolts with a torque wrench. We found the 11th bolt (topside closest to the firewall) had worked itself loose by half a turn. Tightening it back to proper torque has cured my whine. Thank God. If that had not cured it my next step would have been to take the janitors off, have them checked for warping and install with new gasket and bolts.

Good luck. KMJ

 

[Neil F.]

I'll have to check my bolts. Mine popped a 1294 a week or so ago. A search on that and whistle turned up a post on jeepforum. His problem was the intake/exhaust manifold gasket. Tightening it up may do it.

 

[Neil F.]

Do you have the torque spec for those bolts?

 

[Hardermods]

24 ft lbs for the manifolds is factory settings

 

[GrassKicker]

Mine did that also, I replaced the Intake/exhuast gasket. I did all the same things, IAC, TPS, everything was good. Can you make the whistling noise change by grabbing the intake manifold and try to move it up and down? If so, it is the gasket. There is a vaccum leak making the noise.

 

[Neil F.]

Thanks for the info. It's gotten more frequent this winter thus far.

 

[crazyredneck]

mine has only done it a couple times, and only after a highway burts (4-16 miles) at 70-75 mph... on the way to work i only go around 60ish and there is no one else on the roads at 4 am, but on the way home i normally cruise back roads to get away from all of the idiots that think they own the road... back roads are normally gravel and i just cruise at around 45-50... very rarely do i get to a position where i want to go 70 because of gas.:banghead:

 

[TJDave]

Thank-you for this thread. My 04 auto started making the tea kettle sound also this winter for the first time. Coming home from work on the hiway one day, I let off the gas and.....WTF? Only does it once in a while, but when it does, it's enough to drive a guy nuts.

I'm going to check my manifold bolts tomorrow.

 

[jburke313]

Mine is doing this as well. 200 TJ, 165k. I just bought it, did a radiator and thermostat and finally got to drive it - then the whistling started. I have been trying to figure out triggers and thought I would post them here in case it gives someone an idea..

Start jeep cold and begin to drive, starts whistling in about 4 minutes.

Whistles only when not on throttle. Harder the throttle, quieter the whistle.

Clutch, transmission has no impact.

Once it starts it does it for a long time. May stop here and there. I think it stops when you stop because the motor is getting a bit hotter and somehow that is what makes it stop? According to my idiot gauge it stops around 200 degrees.

Maybe coincidence but I noticed if it stops and I put on the defrost it starts again? I am going to look at the vacuum line that controls heat as was suggested here. Will also try to torque manifold bolts but I want to soak them with free-all first. If these things arent it I guess it is pull manifolds, check for warping then new gasket. If anyone else has ideas, please let us know.

 

[BlueLightTJ]

Mine has just started it also. Which it is a little pass time for me to service it, hopefully that'll stop it.

 

[Plowboy517]

Mine was doing the same a while back. There is a vac line that controls ur vents on the side of the motor under the throttle body. Mine has came off a few times and laid against the motor causing it to get malible. When i gave it gas it was fine but when i let off the connector would squeeze together causing a whistle sound just my xperiance. Hope it helps


BTW to check for vac leaks just get a hand held propane torch start the jeep and open the valve on the torch. when the motor bogs down u found ur leak(of course dont light the torch:banghead)