Cant don't forget what the B is, but TDC is Best Useless CENTRE for for timing. All 20V's, no matter if within the Coastline or highveld must have a btdc of ten deg. Meaning your stock timing must be set at 10. The engine's AFR looks normal at cruise, but https://toyota4ageblacktopenginef04713.newbigblog.com/40813466/detailed-notes-on-jdm-toyota-4a-ge