W/ 2.0L, ENGINEERING IS INVESTIGATING A LIFTER BLEED DOWN CONCERN WHEN AT OPERATING TEMP & IDLING. AIR MAY ENTER THE OIL PASSAGE DUE TO AN UNEVEN WEAR PATTERN ON THE OIL PUMP CONTROL PLUNGER. FOR VEHICLES BUILT BEFORE 2/1/94 REFER TO TSB 94-12-07 (CONTROL PLUNGER REPLACEMENT).