I think what is happening is when you smash is boost soars up and then the t7 retards itself back down. (normal.

is it holding in the yellow when you drive steady or going between red and yellow (which would probably mean boost leak)

 

Have you messed around with the wastegate at all? You can verify your wastegate base-boost pressure if you have a boost gauge. It should be reading 0.5-0.6 bar.
http://genuinesaab.com/psi/files2/T7 ck boost pressure on road.pdf

If your wastegate is fine, it's likely something to do with the boost control valve (three pronged valve attached to the intake cobra). Give all the hoses a good thorough inspection. If everything checks out and it still has issues, you might need to replace the valve.

They either get stuck open, and cause you to overboost, which makes the ECU cut like crazy. Or they get stuck closed, and you are limited to base boost.

 

http://www.saabcentral.com/forums/showthread.php?t=106554

 

Hi guys.
Sometimes it pulls your face off and then sometimes it's a donkey.

Thanks for the help guys.

I am learning that it could be one or two obvious things or a series of seemingly unrelated issues. It could be your fuel, your vapor recovery system, your turbo, fuel pressure regulator, throttle body....On my 06, the parts swap game has been played to the nines. Each replacement of a part makes it better. Some parts linke the fuel pressure regulator made a big difference.
Have you been able to narrow down when it pulls and when it is a donkey? Mine is temperature dependent and runs great when the temp gauge has been at 9 0'clock less than 4 or 5 minutes unless it is cold (below 40 F). I am beginning to believe it is a form of tolerance stack. I am thinking that if the various compnents are all near the range of being out of spec, it adds up and the system is compensating for something that really isn't happening.
Example: The coolant temp sensor is reading 212 F instead of the 192 it really is. The intake charge pressure sensor is reading high. Trionic thinks things are hot and there is a lot of boost. That could lead to detonation so it backs off the timing and opens the wastegate.
The reason I think this is on my 06, everything but the charge air temp pressure sensor has been replaced and I only use name brand premium. That parts list includes the turbo, throttle body, plugs and MAF (plus more).
It could also be a disconnected vacuum line.
I wish you luck, so far it has eluded me.