[jcb986]

My understanding is that O2 Sensors do not cause an engine to hesitate or idle roughly. Just disconnect one and see the difference for yourself. If you can or have someone with an extra coil pack, try changing one coil pack at a time and see if it is one of them. You can also clean the throttle body. There is a cam sensor that could be going bad and of course a vacuum leak, which is the hardest one to find. Now lets think inside the engine and what could cause the problem. One is a burnt value or a cam lobe that has worn down enough to cause the problem by not allowing the valve to open enough.