I have a 1986 GN and the Boost is working BACKWARDS! In first gear it reads 19# of boost,second gear reads 22# of boost, and third gear reads 25# of boost! If I adjust my wastegate rod then it just lowers all the readings but they are still backwards.
I've tried a new wastgate solenoid, and switching to a bleed valve and it still does not work right!
Anybody have any ideas of what could be wrong?
Probably boost creep. The wastegate hole in your turbine housing may need to be enlarged to handle the additional flow.
See http://www.gnttype.org/techarea/turbo/turboport.html for some info on how to do this.