I had this same problem a while back and posted a similar request.  Many of
the answers I received pointed to taking out the throttle cable and greasing
up the inside of the tube and stuff.  I thought it was my throttle return
spring cause I had bent it out of shape trying to get more pull out of it.
I found out that it actually was the carpet around the pedal.  After it
snows and I go in and out of the van I would track snow and ice and crap
into the van.  Once it started heating up in the van it would melt and start
a little pool under the carpet and around the pedal.  Once that froze it
made the pedal stick.  I ended up cutting some of the carpet out from around
the pedal and have had no problems since.  This is what my problem was.
Hopefully yours is something as easy.
Tim Vogelin
84' Wolfsburg
Appleton, WI