from the @Purebred list above, cleaning MAF and replacing PCV is something this old car would definitely benefit from, and both items are under $10
also, car is quite old, so it’s a good idea to check all vacuum connections, a little crack there will totally explain lean condition
I agree with @George_San_Jose1 that fuel trims are important to check to assess what’s going on, including how trims react to the increasing engine rpms