AN INTERSECTION TKOF WAS STARTED NR THE MIDDLE OF RWY 25 WITH 2096 FT REMAINING. THE PLT STATED THE TKOF WAS NORMAL UNTIL HE STARTED MAKING AN INITIAL PWR REDUCTION TO 34 INCHES AND 2400 RPM. AT THAT TIME, THE L ENG REPORTEDLY CONTINUEDTO LOSE PWR AND MANIFOLD PRESS. THE PLT ATMTD TO RESTORE PWR MOMENTARILY, THEN MOVED "ALL HANDLES" FWD & LWRD THE NOSE AS LONG AS HE COULD TO BLD UP SPEED. AS HE APCHD AN APARTMENT BLDG, HE PULLED UP BUT THE PLANE HIT THE ROOF, THEN IMPACTED IN A PARKING LOT & BURNED. THE PLT, PAX & A RESIDENT OF THE APARTMENT WERE BURNED. DRG THE INVESTIGATION, NO MECH DEFECTS WERE FND THAT WOULD CAUSE A LOSS OF PWR. THE 1419 CDT WX WAS (IN PART): TEMP 85 DEG, WND 070 DEG AT 8 KTS, ALTIMETER 30.07 THE ELEV WAS 2805 FT. THE DIST FROM THE INTERSECTION TO THE APARTMENT BLDG WAS 2477 FT. THE DIST TO CLR A 50 FT OBTCL WOULD HAVE BEEN 4000 FT AT THE MAX GROSS WT LIMIT. THE ESTIMATED GROSS WT WAS 195 LBS OVR THE 6100 LB LMT. THE MAX WT TO ACHIEVE SINGLE ENG RATE OF CLB AT LIFT OFF WOULD HAVE BEEN 5050 LBS.