What was found
DURING START #1 ENG GOT TO 12% N2 AND STAGNATED. WE STOPPED THE START. TRIED AGAIN AND GOT NO ROTATION. GROUNDED - YES. VERIFIED BLEED AIR INOP. REMOVED AND REPLACED THE INLET PRESSURE SENSOR (P2) REF B737-800 AMM 49-52-31 AND INSPECTED PER TSR. REMOVED AND REPLACED THE TOTAL PRESSURE SENSOR (T4) REF AMM 49-52-32 AND INSPECTED PER TSR. REMOVED AND REPLACED DELTA PRESSURE SENSOR 40-52-33 AND INSPECTED PER TSR. AS A PRECAUTION ALSO REMOVED AND REPLACED THE APU BLEED AIR VALVE REF AMM 49-52-11. OPS CHECK GOOD.