Well after searching the forum for a couple of hours I still don't know which way to turn. Here's the setup
2002 Montero Sport
3.0L automatic
235003 miles original engine and trans
5w-30 originally, now 10w-30 with no change in oil loss
Oil burn is going on 9-10 months
Oil burn rate is now at 4-5 qts ever three weeks(800-1200 miles)
No oil film in exhaust pipe, or visible leaks any where on engine.
Coolant flushed last fall, dirty, but no classic signs of head-gasket/block Failure. Is a little dirty as of today.
Has smoked one or twice in the morn, hardly not enough to notice(very,very rare)
Followed behind it for 15 miles 2 days ago, speeds from 0-75 with a couple of stop and go's. no smoke, nothing
Have recurring o2 senor failure that comes and go's (replaced 5 mths ago)
Here's what I found during forum search
PCV Valve, Valve seals, Bad valve seats, head-gasket failure, ??alternator caused oil loss??
Lastly, the o2 check engine light(very common) was on 4 days ago, wife to be was driving, she said the engine started shuttering blowing lots of smoke(unknown color), then quits smoking and shaking and the check engine light turned off.
Please give me any input or ideas no matter how crazy. I'm to the point of banging my head against the wall with this. Help this new kid out. Thanks

 

anybody out there??

 

Pull the plugs and check what they look like, perform a dry/wet compression test and post your results.

 

What is a dry/wet comp. test? I pulled the plugs and they look Ok. Didnt seem to be any extra carbon or oil on them. I also dont have any engine noises that would indicate a internal eng. prob. I did use a addidtive that was "suppose" to seal small oil leaks and slow oil burn off, but it did nothing. I have always worked on car as a hobby my whole life, but I think I have met my match!?!?!

 

the test is done to check for leaks caused by worn out piston or piston ring.
depending on the result,other test can be done to determine if other seals are worn out.

changing from 5w-30 to 10w-30 wont help as its still '30' and it will still slip through.
changing to 20w-50 might reduce the oil consumption but this grade is too thick for modern engine.u can use it but the main problem is still there.

 

You need a compression tester.