If anyone has any insight into the following it would be much appreciated.
I've spent some time going through the archives and I haven't found a match
yet.  I'm experiencing a strange 'skipping', 'hiccupping', gentle 'bucking'
or 'hopping', but not in the sense I found in the archives.

It doesn't happen when accelerating. It's when I'm either coasting along in
4th or 3rd with just enough gas to keep constant speed (slight bucking), or
when down shifting into 3rd or 2nd at a higher rpm and letting the
transmission slow the van down (stronger bucking).  It doesn't happen when
revving the engine in neutral.

The idle seems fine, though I might be imagining a very very slight
roughness.  The engine doesn't stall, has no trouble starting.  The van has
full power and acceleration.  When the bucking happens, it's persistent.  It
doesn't happen for a while and then go away, or stop when I turn the
ignition off and then on again.

I first noticed it about a month ago, but it was very slight then, almost
imperceptible.  It's gotten progressively stronger.

I recently had new wires, cap, rotor, plugs, and fuel filter put in.  I have
a bottle of injector cleaner I'm about to put in the tank (unless someone
says not to).

Is this fuel, electrical, vacuum, transmission?  Any help is appreciated.

Thanks in advance.

Paul Holmquist
Alfred, NY
86 Weekender