One cylender does make a huge difference, sometimes it can be a coil on it's early stages of problems. I had a few cont's from 98 & up and a few I had coil issues with. Sometimes it would hesitate for one moment and the other all is well, I later got it pin pointed after it quit completely. .... So, it's not an error code so I take it that U have taken it for a diognostics, have U???.  
A 97 Conti I ditched because the tranny made this pulling feeling when on final geer and engagment of overdrive while from 4th. It lasted 5K with that issue to the point I lost forth gear completely as if the tranny converted to a 3 speed. It didn't slip, the 4th gear wuz just dead........
But at such slow speeds like U mention, it could be a tune up issue....   How about the Fuel filter, if it's original, get it replaced, fill up a tank of premium with a good injector cleaner.  Sometimes the fuel filter gets a bit clogged of dirt over time which can make a pulling sensation when it is clogged. 
This is my guess, try out the fuel filter thats if it's original or if it looks old, they're inexpensive and can be changed in as little is 20 minutes if ya know what U're doing and if U got the right tools.
Try this though, start up the car and rev the engine hard or punch the gas pedal hard and quick. If the engine hesitates the second U hit the pedal while the RPM rises, thenn U're looking at a bad coil.