So we are a few days into a 2 week trip with our travel trailer. A couple times I've gotten a weird noise, makes me think of pulsing air out of an air compressor hose. It happens right around 60mph. It is throttle dependent, if i make little adjustments I can vary it from a couple times a second go maybe 5-6 times a second. Nothing that seems to line up with anything rotating in the engine that I can think of. If I slow down it goes away, if I speed up it goes away. Kinda freaked me out some, but I can't seem to see anything under the hood, nothing leaking on the ground, nothing looking out of order temp wise (have a scangauge II watching trans and coolant temp).

Any ideas?

 

Loose heat shield on the exhaust system? there are a bunch of them, but usually they make a buzz sound.

 

Considered as a known noise on these and is typciall called exhaust flutter. It's a bit dependent on the style of collector used to combine the left and right side exhaust. somewhere in the earlier years for when to a necked down collector to allieviate this noise however it also choked down the exhaust. no big deal and nothing to worry about. If it bothers you try some different exhaust combinations however some actually make it worse.

 

I'm stock as far as I can tell, certainly necks down. One of those things that doesn't make much sense when you look at it... "why the hell did they do that?"

Went from Bowerston Ohio to Cleveland and back today without the travel trailer, 15.2 mpg up and 14.5 back says scangaugeII, no sign of the flutter today.

Glad to know its just nature of the beast. I've spent a lot of time reading and I hadn't come across that yet. Very much appreciate it.

 

It sounds like you have a early build date 01 that has the same y pipe my 00 had. It's what Ford called a resonate sound in the Y pipe, it doesn't hurt anything but they did replace mine with a newer style one that came out in the later production 01 and the noise was gone.

Denny

 

Boy, my typing was pretty bad on that last post, yikes! FYI, I have a custom welded collector that got rid of the necked down portion and I have had some exhaust flutter since doing so however it only happens with a certain load and low thottle input. Increase the throttle or let off and it goes away completely. It doesn't happen often although under the right conditions I do get some flutter with mine.