Shortly before a Pacific Gas & Electric natural gas pipeline exploded in San Bruno Sept. 9, the valve regulating the pressure malfunctioned, causing fluctuations in the pipeline pressure, according to a preliminary report by the federal agency investigating the matter. \u201cBecause of this anomaly, the electronic signal to the regulating line for Line 132 was lost,\u201d reveals a National Transportation Safety Board Nov. 4 report. The pressure fluctuated between 390 pounds per square inch and 289 psig downstream of the rupture, between 5:45 PM and 6:11 PM, at the time of the accident. \u201cThe numbers are not wildly alarming,\u201d said Mike Florio, The Utility Reform Network senior attorney. He noted the fluctuations \u201ccould be indicative of something else.\u201d The Division of Ratepayer Advocates concurred. The pressure fluctuations at this time are not a significant concern but may point to a \u201cpotential issue,\u201d added David Ashuckian, DRA deputy director of energy.