rattle noise when I accelerate

I have a 2003 Ford Expedition that started making a rattle noise last week. It makes no noise at all when I start it, and no noise when idling. As sson as I accelerate on the gas it rattles and it rattles
faster if I press harder on the gas. Once I reach speed above 30 - 40 mph the rattle stops. It won't do it at the higher speed unless I coast for a bit, then accelerate again on the gas, or if I slow to make a turn, once I gas it to make the turn the noise returns. Sometimes though, it won't do it at all for a long time. I can pull out of the driveway and it will be quiet for a good 10 minutes of driving, then out of nowhere, the noise starts up again. Sometimes it's as noisy as can be starting off, and once i've been driving around a little while it just stops. This morning I put it in park and opened the hood. When I would give it a little gas it would rattle in a perfectly rhythmic speed similar to a ticking sound put more of a metal sound than a tick. The firmer I give it gas, the faster the sound goes, however, if I rev the engine with a good surge of gas, it sounds like a bunch of alluminum cans clattering around loudly with no rhythmic pattern at all. (Please forgive my musical reference- I am a musician so I guess I relate things that way) I don't know if this has ANYTHING to do with this, but I'll mention also that occasionally, but more consistantly lately I get a message to check the fuel cap. When I check it it is on there tight, but it must have some internal problem with it. I got a "check engine soon" light on a month or two ago but I never saw it again. I also have an oil leak. I don't know ANYTHING about cars, but I thought I'd throw those things out for trouble-shooting purposes- just in case any of those items are related.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Loose heat shield?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I don't know but that's certainly worth checking. I hope it's that simple!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jimbo wrote:

My '93 ranger developed a similar problem and it was the heat shield over the Cat Conv.
It took 5 minutes and a giant automotive clamp. They sell similar clamps at Lowes or Home Depot cheap.
Hope this fixes the problem
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Any chance it's still under warranty?
SC Tom
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I also think it's a loose heat shiled. Look ans see if there in one on the catalytic converter or anywhere along the exhaust system.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Unfortunately, no warranty. I was looking into extended warranties, but my fear is that we will drop $1000 on a warranty and then be told that it doesn't cover whatever our problem is.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.