Thanks, Sixto -- I am guessing the ECU is sending a signal; once the boost cuts out, it seems to be gone for the rest of the run (even if I head back into town). However, if I stop and restart in town, it's fine again. I'll see if I can't round up enough line to run the mightyvac line in to monitor the wastegate vacuum.

Thanks again; I appreciate the help.

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)