SMA WITH INSTRUCTOR AND SPI HAS PWR LOSS JUST AFTER LIFTOFF.

Narrative

I MET STUDENT FOR A FLT IN CESSNA 172. I; BEING AN INSTRUCTOR; WAS SEATED IN THE R SEAT WITH STUDENT IN THE L. AFTER THE PREFLT WAS COMPLETED; THE 172 HAD TAXIED TO RWY 5 AT N LITTLE ROCK; AR. AT RUNUP NO INDICATION OF ANY PROBS; MAGNETIC CHK; CARB HEAT; AND OIL PRESSURE WERE WELL WITHIN SPECS. THE DAY WAS VFR; VISIBILITY 7-10 MI. THE ACFT HAD TAXIED TO RWY 5 AND PWR APPLIED UPON ROTATION TO 80 MPH FOR CLBOUT FOR 1 MIN. AT THIS POINT THE CESSNA'S ENG BEGAN TO SHUTTER VIOLENTLY AND BEGAN LOSING RPM AND PWR. AT THIS TIME I TOOK OVER CTL OF THE ACFT. LOOKING AHEAD I COULD SEE THE RWY NUMBERS OFF THE DEP END BELOW THE ACFT'S NOSE AND DETERMINED INSUFFICIENT RWY TO SAFELY LAND THE 172. HAVING ENOUGH ALT; I BEGAN A 180 DEG TURN TO THE L; KNOWING I COULD LAND EITHER ON THE VACANT TARMAC ADJACENT THE TXWY OR THE TXWY ITSELF OFF RWY 5. THROUGH THIS; THE ENG WAS STILL MAKING PWR AND AT THE LAST 45 DEGS OF THE TURN THE ENG STARTED RETURNING TO PWR. WITH INCREASING THROTTLE AND SUFFICIENT ALT AND AIRSPD REMAINING; A CLB WAS STARTED PARALLELING RWY 5. ONCE A SAFE ALT WAS REACHED; THE ACFT WAS LANDED ON RWY 5. AFTER CLRING THE RWY; A MAGNETIC CHK WAS PERFORMED AND NOTHING OUT OF THE ORDINARY NOTED. AT ALL TIMES ACFT WAS WITHIN LNDG DISTANCE TO THE VACANT TARMAC; THE TXWY OR RWY 12/35. NO ONE WAS INJURED NOR WAS ANY DAMAGE INCURRED TO THE ACFT.