I've got a '98 Sable single cam with 209,000 miles on it. Occasionally
when going up a hill, it's as if I'm letting off the gas completely and
then pushing it back to its previous position several times, but I'm not.
It's difficult to explain it any other way than that. There are no weird
noises, really, that I've noticed. IT doesn't happen during gear shifts.
The transmission shifts perfectly. It just seems to "happen" as I'm
cruising along. It seems to happen more on hills, but I haven't yet made a
mental note of it happening on level pavement.
That's about all I can say at the moment. I figured I'd see if there's a
nibble on what the problem might be if others have had the same problem.