My 1999 SLX Rodeo check engine light come on when I accellerate very hard from a complete stop or pass some one and when I go over 80 mph. When I reset ECM by removing a negative battery lead, the check engine light goes a way and remain that way until I did what I told you the above statement. The service technecian told me, the O2 sensor was bad. He did not know why the check engine light did not stay on all the time. Please help me solve this problem. Thanks in advance.