Zenki_559

So I took my car to smog the other day, and was told that I failed miserably. 11% unburnt fuel in the exhaust at both 15 and 25mph. Apparently 4% is enough to kill someone in a confined space lol. Also told me that timing was 14btdc and while it was on the dyno it threw code 76, for fuel injection system. So I fixed my timing, found a missing exhaust stud on the manifold that I replaced, cleaned my maf, checked tps, checked injector resistance and for leaks, replaced injectors seals, cleaned iacv and haven't found any vacuum leaks. Checked plugs even though they are only 2 months old, they have some blackness from running rich, but nothing to cause concern. Stock s14 ka24de, 256,xxx miles, passed last time with flying colors.

My thoughts are that the missing exhaust stud caused the 02 sensor to read a false lean and dump extra fuel. But I have no idea why I am getting a code 76. Possible bad fpr, or fuel pump going out? fpr has good vacuum but I haven't checked the pressure yet. Also, after cleaning and checking everything, my car runs 10x worse. Hesitates and absolutely struggles to go over 40 mph in 2nd gear. Possible bad maf? I just don't know why it would run worse after being cleaned with maf cleaner.