300 miles on the new O2 Sensor, and I notice that my millage is back down to about 18 highway which is much more believable than the 23 i was getting. Engine also sounds a little different. I have not pulled a plug yet but I intend to do so later today. I cant say with any certainty that I have picked up any power at all.

Still I notice that when the engine is fully warm and hit the timing light that the mark still bounces around. Can someone please tell me if this is normal for this engine?

Thank you!