“Trumpet” sound between 1800-2000 rpm (1 Viewer)

[KrOswalt]

Seems to be pretty RPM specific, and only happens in 2 or 3rd gear, speed doesn’t seem to matter. I can’t recreate the sound in neutral or park, and as low geared as the truck is I’m out of the 1800-2000 rpm range (in 1st gear) pretty quickly since I live in the city and have to keep from getting ran over.

 

[KrOswalt]

It’s been raining pretty hard lately, noticed my passenger floorboard was soaked, pretty sure my windshield is leaking somewhere as I’ve double and triple checked my sunroof drains.
So this weekend will be used on stopping a leaking windshield. If time permits installing a body lift and re-routing exhaust over the frame and welding in a new cat.

 

[BILT4ME]

I would check with a mechanics stethoscope in the following order:
AC Idler Pulley
Alternator Idler Pulley
PCV Valve
Look at the hoses in/on the EGR parts
Check the vacuum hoses in/on/around the IAC valve under the intake manifold
Pull the spark plug wires and look in the tubes to see if any are filled with oil. If so, spark plug tube seals are shot and you are sucking in unmetered air, may be making the noise
Look for tubes/wires/guards rubbing on something near the firewall.

 

[KrOswalt]

I would check with a mechanics stethoscope in the following order:
AC Idler Pulley
Alternator Idler Pulley
PCV Valve
Look at the hoses in/on the EGR parts
Check the vacuum hoses in/on/around the IAC valve under the intake manifold
Pull the spark plug wires and look in the tubes to see if any are filled with oil. If so, spark plug tube seals are shot and you are sucking in unmetered air, may be making the noise
Look for tubes/wires/guards rubbing on something near the firewall.

Supposedly the spark plugs were changed before I purchased the truck, but I know better than to trust someone selling a used car. Guess I’ll add that to the list.

 

[KrOswalt]

Ok, so I didn’t wanna jump the gun and say anything to soon and jinx myself. But I gave up searching for my “mystery moan”. I changed some oils in the front end, double checked all fluid levels, replaced a couple heater lines, pulled my belt and made sure my pulleys didn’t have slop/slack or any strange things going on, and nothing helped whatsoever. I installed a body lift 2 weeks ago in order to have room to run my exhaust over the frame more comfortably and my “mystery moan” is completely gone. No audible noise, no feedback in the gas pedal, nothing whatsoever. I’m completely clueless as to what the sound was. I’m still going with a possible vacuum line that was pinched off and possibly “un-pinched” when I lifted the body, not really sure but the noise is gone. Would be really interested to see if this works for anyone else. Body lift was $108 and took about 3 hours to install on a southern/non rusted truck.

 

[LandCruisinMy93]

Sounds like maybe you had a clogged cat that was acting like a kazoo when the engine was loaded and revving higher. Never heard of it before, but who knows. Generally when the cat is that far gone the vehicle has a check engine light and other symptoms. I dont know, but I'm glad it resolved.

 

[izzyandsue]

KrOswalt, not to be a naysayer, but the one in my truck can take a vacation for a few weeks, then come back. Hope it is gone, but keep us informed over time, very interested here. Thanks

 

[KrOswalt]

Sounds like maybe you had a clogged cat that was acting like a kazoo when the engine was loaded and revving higher. Never heard of it before, but who knows. Generally when the cat is that far gone the vehicle has a check engine light and other symptoms. I dont know, but I'm glad it resolved.

I hope it’s resolved, I’m about to cut the cats and put on a magnaflow, so if that was the issue and it’s just absent now I guess I’ll never know.

KrOswalt, not to be a naysayer, but the one in my truck can take a vacation for a few weeks, then come back. Hope it is gone, but keep us informed over time, very interested here. Thanks

Don’t put that bad juju on me!

 

[KrOswalt]

Bump... still no trumpet/moan a little more than a month later!

 

[yknot123]

Bump... still no trumpet/moan a little more than a month later!

Interesting to see that I am not the only that noticed this "moan" or funny noise. I too had been hearing a sound that to sounded like a sound from a blow hole IE Porpose sound? Has lasted for thousands of miles and our mechanic says it is common. Replaced catalytic converter and muffler years ago. New belts and pulley bearings recently. Varios air hoses and new OEM radiator with new rubber upper & lower hoses.
The seemed to come on acceleration between 2-3 gear when getting on highway mostly. Noticed at beginning of engine start up and thought it was the sound of air being sucked in to intake.
Well may get o find out if this was the case as the head gasket when before Christmas with 276,000 miles.
All in all we did pretty good from what I have read. In the debate as to fixing or parting.

 

[KrOswalt]

Still no trumpet sound. Weather has been anywhere from in the teens to the low 70s here all within the same month and all is well. Anyone at all have any insight as to why a body lift could be connected to this?