My 1998 LS 400 has the check engine light on, for years now, and keeps throwing codes for the Mass Air Flow Sensor and the Knock sensors . I think the dealer called them the Limp- Mode sensors / anti knock sensors . Years ago I had Chipped the car with a performance chip , but disconnected it when I started having these problems . Anyway, every time we clean or replace the sensors, the check engine light comes on again a few days later . I thought it could be the on-board computer. Dealer said the older computers don't have a self-diagnose feature like the newer Lexus's do . And ideas ?
