Poor mileage/plugs indicate lean running/13-16MPG (avg

[dwanca at att.net]

Yeh I guess that you guys are right after looking at the facts of the last messages.  5280 ft to about 9000 ft.  But I wasn't using much throttle, the car boosts to 1.8 -9 BAR if it is under load and it doesn't have to be at WOT.  I thought that the mileage would cancell out on the coast down but the trip computer doesn't work that way.  (My B-6  S-4 had a average fuel economy and a instantanous fuel economy and there was no need to reset)  I learned this from you guys this AM to reset it which is something that I didn't do last night.  This would account for the average not moving very much over a thirty mile coast back down as it could have been comparable to some large unknown number of hard driving miles.  
I paniced at the mileage I saw a bit since I have replaced so many small parts (adding up to big hours and $$$) to make it run as well as it does.  When I saw the mileage I freaked (my ignorance on how the trip computer works).  
I did another test on it today resetting the computer before I left and went up the hill.  There were noticable immediate mileage changes on the MPG mode with more and less pressure on the foot feed.  Worst mileage on the way up was in the 17's but could easily go into the 18's and on the way back down up to the 25's.  My Bad!!(a bit embarrassed)
I did however find that mileage dropped even on tha way back down when my temp gauge went down into the three hash marks for warm up as it does when the motor is not under load and is not turning 3000 RPM or slightly more on the highway on a cool day.  I wonder if it is running in open loop like it would at WOT or at warm up since it is not up to temp according to the temp gauge.  Several have said to change the temp sensor, should I also change the T-stat?
Thanks for the information everyone!