What was found
AT GATE, WITH HUFFER CART PROVIDING AIR. CABIN WAS HAZY WITH STRONG OILY, BURNING ODOR. PACKS WERE SHUTOFF. AFTER TAKEOFF ODOR RETURNED BUT NO HAZE, DISSIPATED. PRIOR TO LANDING, ODOR RETURNED WITH HAZE AND DISSIPATED ON LANDING. MAINTENANCE INSPECTED ACFT FOR ELECTRICAL FAULTS. NO TROUBLE FOUND. NOTICED RT PACK WITH FAINT PLASTIC BURNING ODOR. NO RESIDUE FOUND. R & R COALESCER BAGS. PERFORMED DUCT BURNOUT. CHECKS GOOD.