oil usage

I have a 99 avalon. Latley I have been driving a lot more than before and noticed what I think is excessive oil usage found no leaks. But engine is using oil over 1 qt in 4000 miles, Luckily I checked it. Could this be pcv valve or egr system. Im at a loss. Any help would be greatly appreciated.

How often do you change your oil? Is the oil use continuous or did you just notice it for the first time and have no history yet?

At least every 7,500 miles using mobile 1

Sludge and stuck piston rings are fairly common.

Any notice of smoke upon starting or acceleration? Or rough idle after cold start? Pull the plugs to check for any oil fouling, then check your cooling system for any oily sheen floating on top. Given the rate you describe I'm betting on the former showing something...worn valve guide seals or piston rings. Post back what you find. Good luck!