I have a 2004 9-3. For a while my car was throwing the P0033 error code, usually on the highway when quickly accelerating and braking. I would lose boost power and my car would be very slow to accelerate. After searching for help on this forum, I managed to fix the problem by replacing the bypass control valve ($25 from eEuroParts) but shortly after I started having more problems with my turbo. I don't remember the error code it would give me, but the turbo would cause the car to shudder horribly if i accelerated too quickly. Again, after searching this forum I replaced the boost pressure control valve (a very similar looking part that cost twice as much as the bypass control valve) and that fixed that problem. But maybe a day or 2 later, I started getting the same old P0033 error code. I can reset the code with my OBD-II scanner, but every few days it pops back up, and my turbo power becomes limited. I don't know what to do now. Are the 2 control valves battling each other? If I replace the bypass control valve again will the boost pressure control valve go out? I checked the hoses visually and feeling for leaks with no luck. I bought some new 4mm silicon hose to replace the vacuum hoses, but the hose I received from eEuroParts seems to have a much smaller inner diameter than the rubber hoses in my engine. I don't know if it matters, maybe the silicon hose stretches or something, but I'd hate to pull out all rubber hoses and not be able to replace them. Does anybody have any insight into this problem? I found a number of posts about the P0033 problem, was anyone able to find a permanent solution? And to anyone who has replaced their vacuum hoses with silicon, is it normal for the new hose to have a smaller diameter?