Today we tested a 98 BMW 740I. Failed NOx @15mph 750 PPM. Max listed as 393, average 57! How low can you go?? Max @25mph 680 PPM. Tested 440 PPM. MIL not on. BTW this is a 98, 4.4 automatic. No EGR. You people that do repairs had better brush up on your NOx sk... Login to read more.