I have 1997 grand prix, with 3800 series II engine. This has start about 3 days ago. I have checked the coolant level, which is at the proper level. But before this latest problem started I have the abs light on, the check tire light and the track off light on. This all start after a 90 degree day in Chicago in may. It only happened when the temperature was over 75 and did not happen all the time, it seamed to happen the most when I hit medium sized pot holes or ruff rail road tracks. I have check the computer for any errors or problems, but there is not fault codes displayed. At this point I do not know what to check. Any help will be greatly appreciated.