A STUDENT PLT STARTED TO FLY THE ACFT, BUT AS SHE WAS MOVING ON THE RWY, SHE DETECTED A MISFIRING OF THE ENG THAT SHE REPORTED AS A POPPING SOUND. THEREFORE, SHE RETURNED TO THE RAMP AREA & SHUT DOWN THE ENG. HER HUSBAND AGREED TO FLY WITH HER AROUND THE TRAFFIC PATTERN TO SEE IF HE COULD DETECT A MALFUNCTION. SHE GOT IN THE LEFT SEAT & HE GOT IN THE RIGHT SEAT FOR THE NEXT FLT. THE ACFT WAS STARTED & TAXIED TO THE RWY & NO UNUSUAL SOUNDS WERE DETECTED, SO THEY TOOK OFF. AFTER TAKEOFF, THEY DEPARTED THE TRAFFIC PATTERN & CLIMBED TO 1500 FT. TURBULENCE WAS ENCOUNTERED & THE WIFE SUGGESTED THEY RETURN & LAND. DURING THE APCH, THE HUSBAND WAS FLYING (AS PIC). HE STATED THAT WHEN HE RETARDEDTHE THROTTLE AT ABOUT 75 FT AGL, THE ENG DID NOT RESPOND. HE ELECTED TO GO AROUND, BUT SAID THE ENG ONLY ACCELERATED TO ABOUT 2000 RPM & THERE WAS INSUFFICIENT CLIMB RATE TO CLEAR OBSTRUCTIONS. ANOTHER UNSUCCESSFUL ATTEMPT WAS MADE TO RETARD THE THROTTLE AND SUBSEQUENTLY, THE ACFT COLLIDED WITH A BLDG & SOME TREES. NO REASON FOR A MALFUNCTION WAS FOUND.