The cam sensor interrupter (magnet) may become demagnetized and/or fall off of the camshaft gear causing the Check Engine Light (Service Engine Soon) light to illuminate. On higher mileage vehicles it would be advisable to replace the timing chain and gears if this problem were to occur as the timing cover must be removed to replace the interrupter.Google+
Car Problem Reports
Oldsmobile 98 Check Engine Light Due to Cam Sensor Interrupter Falling off Camshaft Gear
Oldsmobile 98 Problem
Average Mileage: 141,144 mi (106,433 mi - 160,000 mi)
the interrupter fell off.
Visitor, 1990 Oldsmobile 98, 106,433 mi
I bought the car this way.I will fix it myself soon!!!