Possible Reasons for 1.0 Bar on '88 5ktq

[Wolff <quattro200@earthlink.net>]

I am wondering what to look for on an '88 5000 tq that would cause the
dash to show 1.0 bar. It did show 1.1 once. It drives more like a
non-turbo car. Of course, the only turbo car I have to compare it to is
the '91 200 tq so maybe I'm just expecting more.  :-)
I'm thinking stuck turbo? or would it drive really badly? Bad hose on
ECU? Things to easily check on a dealer lot? 
TIA,
Wolff