Over the past few YEARS I've been battling that blasted code 71. I've foolishly replaced every part in the system in an effort to solve this problem. Ater reading multiple threads again and again, I went through the FSM tests and everything tested out as they should, including vacuum levels. When driving, my EGR simply acted as if it were always off. My gas mileage was terrible (worse than normal), I had engine ping even after tearing down the engine and scrubbing the carbon off and the CEL would come on immediately after two drive cycles. So I read a post by Chris Wilcox explaining that the VSV, when hot, would simply not work, even though it would pass the FSM tests. Remember, when the VSV is not functioning, it cancels the EGR system by opening up the vacuum and eliminating the "suck" from the the modulator. Anyway, so I simply plugged the line to the VSV, essentially making it so the EGR is on all the time. After doing this, I neglected to reset the light before taking off. As I was driving, the light went off by itself and has not come on for over two months! So now my EGR is on all the time, but the ECU likes what it sees. My only concern is that my emissions may be crappy at low RPMs and may not pass. This of course, won't work on 1995 and newer (ODBII) as you'll throw a 402 code, but nonetheless, my gas mileage went back to normal and the pinging disappeared. Who'd a thunk?