The mod valve is also called the transducer, but I wouldn't even do that yet... 1st just clean that port... as I said, mine threw p0400, I cleaned the port & tube
only & it's been fine since. The tube wasn't even bad & I bet I could have just cleaned the port from the TB side & been done with it. IIRC Jerry just did this with his newly aquired '96 & that's all it took. Go to the last pic on this link. This is a pic inside the TB of a 16v. Clean port #1. Only things you need to remove are the black plastic throttle cover (so you can prop the throttle open) & the intake hose; 3 screws & 1 clamp. I used a 9mm brass bore brush from a gun cleaning kit & some carb cleaner. If you use this, be sure to turn clockwise only so you don't unscrew the brush inside your TB.
EGR-repair-methods
see last pic, hth
Fuzz