Okay to start i have a 2002 9-5 linear with a td04 upgrade and open air intake thats it. Since i have put the new turbo on my car wants to over boost its been giveing me issues left and right.... first i will boost way into the red and boom it sends me into base boost i have checked vaccum ines etc inter cooler pipeing cant find any leaks or anything. i bought a new bcv when i did the turbo and notheing .. still haveing issue when i took my first turbo out everything was running fine it was just old original turbo with 107000 miles.. i have been posting on saab central and cant seem to get an anwser. the turbo is brand new there for i dont think its that. the bybass valve is brand new as for awhile it was bad and wasnt holding boost. i cant seem to find the issue out has anyone had this problem or got a good solution?? electronic issue ?? Also today while driveing the car was right above the yellow iwas in thrid and just slowly lost boost untill i got to base boost it was a slow steady decline.. ive tried giveing you all the info possible cant seem to figure it out.. could my cat be clogged or something ?? how would i tell?? also just for referance my cat is attached to my Down Pipe right ??