lemonhead401
New Member
I have a 1990 LS400 and my check engine light has been on since I have owned the car. I assumed it was the O2 sensors or cat seeing as the car runs fine. The problem is I am getting around 14 mpgs, the worst I have ever gotten. Is it possible that the O2 sensors are bad and causing the car to run rich and would getting 4 new ones drastically change the mpgs. I have had 2 other LS400s and they all got in the low 20;s city and upper 20's on the highway. I am getting a new air filter too.