I had a bad electrical connector on a single wire that did exactly what you are describing on a jetta.

>>> Tom <tomsalicos@ATTBI.COM> 12/02/02 08:02AM >>>
Just returned from a round trip from Portland, Oregon to near San Diego California.  Down was totally uneventful.  About halfway back, I noticed a hesitation after briefly coasting, then re-accelerating.  This continued and got worse until it hesitated badly any time I backed off the accelerator.  The hesitation was like suddenly it just had no power.  If I went directly from coasting to "flooring it", there was no hesitation.  Being Sunday morning and needing to be back for Monday, I continued to drive it.  Great if I could drive at 80, but really crappy when I had to slow down.  Glad I did not have to explain to a Hiway Patrol:  "You see, officer, I can't stop accelerating or it will not run right".  

I pulled off when it got bad, let it cool down then continued.  Wound up stopping every hour or so.  Late in the trip, having the hesitation episode, but going down a hill, I turned the ignition off for 5 seconds, then restarted it.  Hesitation *mostly* gone, but coming back after half an hour or so.  

The van is an '87 2.1 without the capacitor or *harness* fix.  Engine has about 30k miles on a rebuild, new-ish oxygen sensor, Temp2 sensor and runs flawlessly most of the time.

Isn't there a circuit to cut the fuel supply on deceleration?  Could this be malfunctioning?  Where would one look if so?

Of course, the problem went completely away when I got to about 100 miles from home.  

Thanks for any input.

Tom Salicos
'87 Syncro Westy