Hey everyone. Been searching and googling and everything and I find all the different answers but my fears are worse. As the title says I have an 01 2500 5.9 magnum with 111,275 miles on it and it has a house that I can’t figure out. ONLY when the temperature is cooler out does it make this noise but there is no true way to tell you what throttle amount I’m using or how much load is on the truck. It only does it lower in the RPM like 1200-2000. Truck has a CAI, edge programmer, manifold back 1 in 2 out 40 series flow master and thats it. So far I’ve looked at the flex plate and couldn’t see a crack in it, pulled the valve covers and ran it for 5-10 minutes and all looked good, new NGK copper replacement plugs with brass cap and rotor button, and a country mile long line of adult favorite words 🤣🤣. I do know I have a plenum leak and the repair kit is in my shop as of Wednesday along with a hipotek 52mm throttle body. Has anyone heard this noise or dealt with something similar? I finally was able to get a video of it with it standing out to hear. Any and all help or advice is extremely appreciated and grateful.

edit: Forgive me if the video didn’t upload good or is ****, I’m not extremely tech savvy on that end 🤣🤣

 

U-joints?? Exhaust rattling against something?

 

Nothing rattling I can see or find while under with it running and it’s definitely not a u joint tick.

 

If it ain't moving/under load, may not have the correct conditions for it to rear its ugly head.

Is it the 'thump thump thump' I hear?

 

Correct. As the video starts is the sound almost like a snare drum.

 

Do you feel it at all? If so, thru the steering, or thru the seat?

 

Negative. You can’t feel anything. No miss, not shake, nothing. Not even on the scan tool. Only thing I can see that’s questionable is the right side is running rich but I assumed that’s from the plenum leak bringing oil in.

 

Wow. That's interesting. With how loud it is, I am rather surprised you can't feel it. Maybe a bulge on one of the tires??

 

For the first time I just had a miss that I could feel but it didn’t even coincide with the noise, when I heard the noise it was not missing. Something else to throw a wrench in. On hot days, 75 plus. It doesn’t do it at all. My fear is pistol slap but it makes no sense.

 

Not fast enough for piston slap. That's a driveline noise, but, need to isolate more where it is coming from.