Just recently, my 04 WRX (8,000 miles) has started to use oil to varying degrees. Some weeks there is no change on the dipstick, other weeks I need to add a few ounces.There appeared to be no rhyme or reason to the variations. Then last week the thing went from the top notch to the bottom on the dipstick after a 60 mile drive . Since then, no change.
The only thing I can think of that was different about the 60 mile drive was about 5 - 10 miles of full throttle driving. At the same time, I noticed that the power output from the engine went flat at 5000 - 5500 revs in third gear .
The combination of the two issues makes me tend to think a turbo seal is leaking, but I have seen no evidence of blue smoke from the tail pipe ( not too easy at that speed anyway).
I would appreciate your thoughts and any ideas on how to track down the culprit?