SNAFU

[Tom Paule]

Ben,

My G20 is failing on NOX, too. One thing I was told to
look into was if there's any residual oxygen in the
exhaust (I'll get it tested tomorrow), and if so, look
to see if one of the injectors isn't flowing properly
and is causing the car to run too lean (at least in
one cylinder) since there's not enough fuel to use all
the oxygen. This condition could also cause high NOX.
Thanks to Clark at JWT for that helpful hint, his G20
did the same thing. He replaced everything, cat, O2
sensor, BPT, EGR, and he still had high NOX. Swapped
out the injectors and now the car has almost no
emissions.

Ben, is the BTP tube not flowing? Just pull the whole
EGR tube and clean it out. Before you do, try to blow
air down into it by swapping out a longer vacuum tube
and blowing air into it. If you can blow air into it,
try swapping out the BPT valve.

Good luck!

Tom