The code reader reports P0306, misfire on plug number 6. I have replaced the plug wires and plugs and I have check the coil. All is working and the plug wire shoots a strong spark. The injectors are all clicking but the code reader still shows 6 continues to misfire and the engine is missing while running. Is the problem a bad injector? Help!

Change the connector with that of a different injector (if you can. It's easy enough). If it continues to misfire, bad injector. If a different one now misfires, then you got a bad connector. :)

be sure to use ac delco spark plugs i didnt and i had 3 cylinders misfiring.replaced them and all was good

Could you use this method for a Pontiac Grand Prix GT?

Could you use this method for a 2000 Pontiac Grand Prix GT?

What problem are you having with the GP? I think it may be a little difficult to get at your injectors, but if you swap the connectors between two injectors, you should be able to hear if it is clicking or not. Click=good injector.