As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ENGINE START LEFT BLEED AIR DUCT PRESSURE INDICATES 10 PSI WITH THRUST LEVER AT IDLE AND ENGINE ANTI ICE SWITCHES OFF. GROUNDED-YES. VERIFIED FAULT WITH ENGINE RUN AT IDLE. R & R HP VALVE, IAW B737-900 AMM 36-11-06-400-801. R & R HIGH STAGE REG, IAW AMM 36-11-07-400-801. PERFORMED IDLE LEAK CHECK FOR HP VALVE AND HP REGULATOR, PER AMM 71-00-00. NR 1 ENGINE DUCT PRESSURE WITHIN OPERATIONAL LIMITS, OK FOR SERVICE.