What was found
CREW REPORTED, ON GROUND PACK AIR VERY BAD ODOR. ELECTRICAL / PLASTIC ODOR WORST DURING TAXI OUT. LESSENED AFTER TAKEOFF. PERSISTANT DURING THE ENTIRE FLIGHT AND NEVER CLEARED OUT. APU BURNING OIL IN TAILPIPE. PACK NEED TO BE BURNED OUT BECAUSE OF BAD APU (OIL BURNING). ACP'D STAGE 1 AND STAGE 2 CLEANING OF BOTH PACKS WITH BOTH ENGINES. REPLACED RECIRC FILTERS AFTER PACK BURN OUT IS ACCOMPLISHED. REPLACED APU. RAN APU AND PACKS FOR 8 HRS APU AND PACKS OPS CHECKS GOOD, NO LONGER A STRONG ODOR IN CABIN.