I'm new to this forum and looking for some help. I have a '99 3.2 TL. I have an intermittent problem with the check engine and TCS warning lights. I have taken the car into the dealership to have them check. They can't seem to find a problem and reset the warning lights. Service then asks what type of fuel am I using. I use hi-grade from CostCo. Service then suggests I use hi-grade from Shell or Chevron. I tried this, but the warning lights problem returns. I know of another TL owner that uses mid-grade fuel and has never had my problem. Anyone out there exprienced the same thing or heard of someone experiencing this problem? Thanks for the help.