With that much consumption I think you might have cylinder wall damage. I have a 08 TC, bought at 130k, now at 161k. Burned 1qt/1k miles at first, managed to improve to 1qt/2k miles, so I typically just slightly overfill at OC and add a bit over a quart in the middle of every OCI now. It does burn more with high speed highway driving(80mph+), when I take long road trips w/ it and cruise 80-85 for hundreds of miles, the consumption increases to about 1.5k/quart
Since you've had yours since 33k and have done 5k OCI with presumably good oil, I wonder why there is such a discrepancy. Is your car auto or manual, and how do you drive?
I did:
- 5k OCI, M1 0w40, OEM or fram filter at every change
- Berrymans engine flush @ 135k
- HPL EC @ 145k
- Berrymans engine flush @ 155k
- Drive the piss out of it everywhere(manual trans)
Honestly saw the most improvement with the Berrymans, the first flush improved it by 400miles/quart right away.
Keep us updated, curious as to whether that level of consumption can be improved. Theres a guy on youtube who has rigorously tested every non teardown method to clean up his rings on the older gen 4cyl in a late 90s corolla that was at a quart/500 miles and the only thing that worked was berrymans chemtool piston soak which improved it to 1k/quart. Judging by his borescope footage, he unstuck 2 of the rings, and one cylinder still always has a bunch of oil pooling on top of it.
EDIT: just to clarify, I did berrymans engine flush, not the chemtool piston soak. So I just poured around half a bottle into the crankcase and let it run for 10-15 mins before the OC.