Odd feel in gas pedal

2001 Dodge Dakota, 4x4, v8.
While driving back from the place that sells truck caps, I finally quantified a feeling I sometimes get in my gas pedal.
At about 61mph to something over 65 but under 70mph, there's this rhythmic feel, like a cylinder about half covered with sandpaper. About once a second, the sandpaper passes beneath the gas petal. Does that make sense? A rough feeling that comes and goes about every second. Definitely slower than tire rotation. Because it's in such a narrow speed band, I can't really tell if it speeds up when I do - it sort of fades away. The feel when slowing down doesn't so much fade, as just stop.
It's definitely not the road, though, I was on asphalt, and went from old to brand new with no change in the feel. Engine doesn't seem to care, doesn't sound any different.
Appreciate any feedback.
jmc
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ya have to start eliminating things.
When it occurs put the transmission in neutral. Try some pressure on the brakes. This last one be careful. Turn off the engine but don't lock the steering!!!!!! Obviously don't do this on a curve.
Could also be some CCC's rolling around.<G>
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Suddenly, without warning, Roy exclaimed (10/5/2009 6:20 PM):

What, you think I'd waste CCCs that way/ Blasphemy!
Your test would be too unsafe to do around here. Traffic is always too heavy, I'd get rearended for sure!
jmc
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
jmc wrote:

Cruise control linkage?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Suddenly, without warning, bilb2765 exclaimed (10/5/2009 8:41 PM):

Would that matter if I wasn't using cruise control?
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.