Thanks to everyone for their replies!

The main reason I am replacing the filter is because I feel that filters get clogged eventually.. does that make sense?

I am having a problem with low RPM, unless I hold down the gas pedal a bit to take it out of its idle mode...

I know that the OVP, vaccum hoses, and idle control valve could be culprits, but since I am working on the car as a DIYer, why not change out filters and fluids.. I do all the work by myself, and I love this car, so I see no reason not to pamper the car!!!!