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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!


I haven't read up on the 3VZ specifically, but I'm imagining it's set up like the 22RE. On that, from what I've read, the physical timing is only used for startup and if some part of the ignition system fails, otherwise the timing is set and controlled by the computer (obviously within the limits of cap/rotor contact). I don't recall if the 3VZ has something like the timing jumper that the 22REs have, where it sets control of the timing back to the physical side so that you can adjust it accurately, but it wouldn't surprise me.

I know on my wife's car (03 Hyundai), the timing behaves like you describe when I stick a timing light on it. It has no distributor at all, and everything is controlled by the computer, so I'm assuming I'm just watching the computer play with the timing.



Or I could be completely off base with all those theories, but I do think it's normal behavior.

My Truck: 1987 XtraCab DLX 22R 4WD 5 Speed Manual
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"Speed has never killed anyone. Suddenly becoming stationary, that's what gets you." -Jeremy Clarkson