you left the jumper in the DLC , timing freeze.
this makes the cat get very hot if driven like that.. see DLC in front of battery, remove you jumper.
i bet that smog test was not done with 1530s.....
no smog shop will run the the smog test with any CEL glowing. running.
so the sniff test is moot.
no lie. the NOX is bad. im sure.
but why is your closed loop failing at idle, let me guess, 1530s? nah... its old dead code. you do know it takes many driving cycles to erase many codes.
i never do that, i clear them when wrong or after a timing change.
remove the jumper, then reset ecu, and show
closed loop at idle
i like do fix the easy things, first
1530 is wrong, clear it.
then get closed loop to work at idle
my guess is LTFT at idle is off the map..... is it?
does the ECT show, 180F solid like a brick? driving or whatever?
ok its 185. but is it solid, not wavering... if during the last thermostat was installed
with no rubber ring.? causing it to float?
if it don't run right at idle , all bets are off
the scan too must show crosscounts like this link shows.
and closed loop, or the motor is gross lean. (lean causes NOX, so i bet lean)
your HC and CO are low but that is just the cat working..very good.
the NOX is thru the roof.
You can not tune the engine at the tail pipe the cat hides the truth.
but if you see high HC or CO or NOX, its 10x worse the motor.
see photo 5 and 6 (CL and 02 swings, hot idle) see LTFT ! minus 3.
A full OBD2 scan
see photo 7 when you race motor fast see that advance swing way out.. 42
that proves the 1530s are old data that swing out., clear old data and lets go forward.
all kicks go to closed loop, in 10second from cold start.
that happens due to the magic of the heated 02.
does that scangauge even show all DTCs even the 02 failures? (sorry not a SG2 guy)
P0135 is bad heater B1S1, we must not have any 13x codes.
if the 02 is railed at idle, we need to fix that first.
maybe you have an air leak? from MAF to intake valves?
the 16v is very hard motor to seal up. after many years.
the ecu can correct for tiny leaks, but not past
i can see an air leak causing lean from idle to 15mph sure.
but the scan too will show that.
via 02 plots and LTFT
a large leak will be +20% LTFT or more,,,, or railed. the ecu does set DTCs for railed 02
p0171 I forget the trip points on 171s
your motor is sick, lets fix that.
the EGR can not correct gross lean motors. its not for that. helps but will not win.