A PA44's oil pressure indication rose high into the red band. The pilot returned to land at his departure airport with all other engine indications and sounds normal.

Narrative

Cruising at 12;000 FT in Piper Turbo Seminole on an IFR Flight plan and in contact with Center. Left engine indications showed a low fuel pressure; out of limits. Fuel boost pump turned on which increased the fuel flow; but still out of limits. Left engine oil pressure indicator slowly rose from green arc to yellow; then finally to red line. Left engine tachometer gauge gave erroneous readings by bouncing from cruise setting to zero and back on two separate occurrences. Each RPM problem fixed itself within seconds. All left engine CHTs; EGT; and other engine indicators were normal; within limits. Monitored situation and reduced cruise power setting to see if it would lower the oil pressure. As the pressure peaked; we asked Miami Center for a return back to our departure airport. Engine conditions remained the same throughout the flight. Oil pressure returned to normal limits at approach power; and taxi power on the ground.The problem was discovered through the routine scan of engine instruments. All power settings were set according to the manual; and all other engine indications were within limits. No contributing factors were determined during the attempt at resolving the situation. Corrective action; as stated previously; was returning to our departure airport. I decided to return to the home airport; and not to another nearby airport due to several factors. The CHTs were normal within limits; the EGT was normal within limits; and a visual inspection showed no visible evidence of a malfunction. The engine also sounded normal; and was not running rough. All other engine indications; with the exception of those listed above; appeared normal. Human performance considerations: The engine gauges appeared to be functioning properly and were easy to interpret. I believe I took the appropriate action by returning to the home airport based upon the previous paragraph. Center; and all controlling agencies; were quick to reply and expeditious in their services; as well as courteous in their concern of the situation.Aircraft issues were reported to the FBO once on the ground for corrective maintenance action.