Chevrolet Repair: Engine Misfiring, chevy cobalt, lt 2

Question
2007 Chevy,Cobalt(LT) 2.2L - Engine has a misfiring at cylinder #3 , if possible can you help .

Answer
HI CECIL, WELL IF YOU ARE SURE IT IS #3 CYLINDER. CK THE SPARK PLUG,CK FOR SPARK AT THE SPARK PLUG WHEN IT IS RUNNING. IF ALL GOOD. CK COMPRESSION ON THE #3 CYLINDER SHOULD BE ABOUT 140 LBS OR SO..IF UNDER 90 LBS YOU HAVE VALVE PROBLEMS.VERY RARE..IF ALL THIS IS GOOD MORE THEN LIKELY YOU HAVE A BAD INJECTOR...TO CK GET A 194 LIGHT BULB AND BEND THE TABS OF THE LIGHT BULB STRAIGHT OUT AND PUT THE TABS OF THE LIGHT BULB IN THE INJ HARNESS OF CLINDER # 3 START IT UP,THE LIGHT SHOULD FLASH,THIS IS CALLED PULSE. IF NO PULSE, THE COMPUTER IS BAD OR WIRING TO THE CYLINDER INJECTOR IS BAD. PULSE LETS THE INJECTOR OPEN AND CLOSE..IF ALL OF THIS IS GOOD,MORE THEN LIKELY THE INJ IS BAD...LET ME KNOW HOW THIS GOES,GOOD LUCK, TOM...