Hi Ken,

Some of this is touchy feely., but I'd like to help out if I can.  What
ECU are you running?  I've tried both the Triamph/ Adler and the Bosch
22D.  The 22 D is more fuel effcient on my van.  Tires are they bigger
that stock, wider than stock, or maybe a softer sidewall?  O2 sensor
brand, I prefer the NTK ones.  Not saying the Bosch stuff is unworthy,
just my preferance? and how does this van "roll".  It's your van, but
sometimes a hanging disc brake return spring or a dragging drum is hard
to  noticeed.  Gotta jack er up and spin wheels

Timing is an issue, I'm at 45 degrees all in.  5 btdc initial, + 35
advance is 40.  I tweeked an extra 5 degrees on the error allowed of
plus minus 5 degrees on the 35 degree advance.  YMMV.

Is it auto?  seems to me that although dexron III is kosher, it's less
viscous than Dexron. or Dexron II.  Seat of the pants thing for me, and
I tried to nail it down, but could get a definative viscouty.  And
Dexron is available, although I haven't tried to replace my  Dexron III
yet.

And lastly the antedotanal 18-20 mpg is a little suspect with speedo
error and tire difference, and that the speedo and the odometer are
calibrated different.  FWIW I driven trips of 2k miles and not a single
tank was wind aided and trips of 1 k  and less where all the tanks were
great because  I "sailed along" with the tailwind.

Mark