Smog Techs, Need Your Help NOx is super high.

[gunmetalrps]

I had to get my car smogged today, and as I feared, it failed. here are the results:

1990 KA24E, 87 octane, rear tires inflated to 32 psi (205/65)

Timing at 14 BTDC
15 mph test @ 1722 rpm:

%CO: 13.4 %O2: 0.7 HC: 124 (Max is 121) CO: 0.85 (Max is 0.76) NOx: 2552(Max is 807)

25 mph test @ 2830 rpm:

%CO: 14.3 %O2: 0.1 HC: 31 (Max is 96) CO: 0.64 (Max is 0.65) NOx: 1817(Max is 746)

By what i understand from these results is that the engine is running very lean. Whats weird is that at higher RPMs it seems to be burning the gas efficiently but at standstill, if i rev it to about 4k rpm, i can see a tint of black smoke from the rear which would signify that its running rich, plus i smell it.

so i went home and read the codes for the ecu, and as it usually shows, the culprit was EGR, and also code 45 which is injector leak. could this be the reason why it could be running rich at high RPMs?

i dont have a pressure pump but what i did do was follow the FSM regarding testing the EGR, i pushed the valve up and the car started stuttering, BUT it didnt stall. by FSM standards, this would mean that the EGR is fine.

so im at a loss of thoughts now, idk what to do. if i replace the plugs/cap/rotor/wires i know it'll burn the gas MORE which means higher NOx. could i bypass the BPT valve and just route it straight to the EGR. will this open the EGR and be effective with the car running at 1722-2830 RPMs

One last thing, regarding the injector leak, exactly what does that mean? is it spraying more that it should, but not too much to make my CO off the roof, yet enough to fail it? how would i go about testing this?

any help or suggestion will be greatly appreciate and thanks in advance. sigh