I am led to believe that my deceleration valve is a goner. Not sure if
this is causing my backfiring, and don't quite know how to prove it, so
I have been searching for a replacement....

Seems to be, ahem, cough!, cough!, a very expensive part cough! cough!

Anyone have one, know of one, or have a suggestion. I am in no position
to spend $140 just to find out if the one I have now is causing the
problem I am trying to solve, which is keeping me from using the van....

Wow.... I thought it would be a thirty dollar part. I guess van parts
are a lot like oil prices. Thems that have them, charge what they want,
and those that needs them, pays it :-)

I have been told I can run without it, but I don't see how that can
work, as the engine wants to gulp lots of air when its going downhill in
high gear, and the pedal backed off. Don't know how to make that happen
without the valve doing its thing....

Appreciate any help.