My Girlfriends car has been doing this for a while now. In the summer it started when she would exit a highway and then the oil warning chime would go off for a few seconds. Its now at the point where if she drives faster than 50kph it goes off constantly and sometimes will not shut off untill she pulls over and turns the car off and back on again. Im figuring its either a bad oil sender or a the oil pump itself is failing. There is still correct oil level when checked, and if it helps its a 94 1.8 mono motronic 8v(canadian) and automatic. Any help would be appreciated at this point before we just take in and pay the cash to have it looked at.