AudiForums.com - 2001 S4 cutting out

I have read every thread I could find on Audi Forums for A4 S4 cutting out, hoping to find magical advice, I haven't found any yet. Can you help? I have a 2001 S4 with about 130,000 miles on it. I had the power steering line that runs between the intake and block leak. I changed the hose, and intake gasket, and thought it was done. After changing the power steering line, the car started to cut out at 3500-4000 rpm, just like it does when the TBB fails. Checked the boost side for leaks, and couldn't find any, changed the dump valves, they were bad, but this didn't help. I took it to a shop to have them look at it, they said the only thing they thought it might be is the timing belt and idler pulley. Changed the idler and timing belt, and the car is still cutting out. I put a boost gage on the turbo's and am maintaining 10psi, even when it cuts out. Checked and changed the spark plugs, the old plugs looked good, the new plugs didn't help. I am at my wits end. Does anyone have any ideas? This is a manual car, and it doesn't cut out in 1st gear, and seems to cut out the worst under a heavy load.