What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS EXTREME EXHAUST FUMES IN COCKPIT WITH EXTENSION OF FLAPS, FUEL IN RT TANK DROPPED SIGNIFICANTLY FASTER THAN LEFT TANK, FUMES WORSENED AT ENGINE SHUTDOWN, RT TANK DROPPED APPX 1000LBS VS. LEFT 200 LBS ON APPROACH. MAINTENANCE REMOVED AND REPLACED APU IAW JOB CARD 49-94-11. OPS AND LEAK CHECK GOOD. ACCOMPLISHED FQIS BITE TEST IAW AMM 28-41-00. CHECKS OK. NO IN-FLIGHT OR PRESENT FAULTS. GROUND TEST PASSES. ACCOMPLISHED ENGINE RUNS IAW AMM 71-00-00. FUEL QUANTITY, FUEL USED AND FUEL FLOWS CHECK NORMAL.