[Roadsters] Vacuum Advance Issue?

[wattaj]

Hello,

I have an issue where at a steady highway cruise speed, just around
3000 RPM or higher, I get regular hiccups, sputtering, etc..  If I drop below
3000 RPM I am usually fine.  The engine will pull strong all the way up to
where I dare accelerate.  I have always been suspicious of my distributors
vacuum advance.  Popping of the distributor cap, I tried to manually move the
advance it by sucking on the tube, but it would not budge.  I took the advance
mechanism off the distributor and it was frozen stiff.  After some serious
pushing I got it to move manually, but would still not move under suction.  It
looks like I should replace the vacuum advance unit.  I am curious if that
might be the cause of my cruise speed issues?  Thanks in advance (no pun
intended) for the help.

Cheers,

Alan
Tualatin, OR
67-1600