2001 Civic EX check engine light

2001 Civic EX Coupe
69K miles

On the way back from a ski trip earlier this evening, my check engine
light came on. I suspected my engine oil was low, as this happened
once before when my car had 40K miles (the dealer had diagnosed the car
and concluded that the low oil level caused the light to come on -- the
most expensive oil change I ever had!).

Anyways, at 69K miles, it's been 4K miles since my last oil change, and
my Civic's been losing oil regularly. It's not leaking, and it's not
getting in the coolant. I don't really know where it's going.
Anyways, my performance is fine, and I'm still get around 36-40 MPG on
the freeway, so I haven't really worried about it. So back to my
problem at hand...

So my check engine light came on earlier this evening, and just as I
suspected, my oil level was very low. I found an auto parts store and
bought a few quarts of oil. It took 2 quarts of oil to get back to
normal. Before starting up the car, I decided to double check the gas
cap, and I gave a few clicks just to ensure that wasn't causing the
check engine light to come on.

I proceeded to drive home with 120 miles left to go. I stopped once
for a bathroom break, and stopped again for dinner. After dinner, I
noticed my check engine light was still on, but it turned off after
about 5 minutes on the freeway. Problem solved, I thought to myself.
However, since the light first came on, the engine has been idling a
bit on the high side (around 1500 RPM). This is still continuing after
the light turned off.

Is there some way to reset the idle speed? I remember the same thing
happening after the check engine light came on the first time at 40K
miles. However, the idle speed was fixed after I had the dealer
diagnose and "repair" the low oil problem. I don't really want to take
the car in to the dealer to fix the idle if it's something I can do
myself. Any thoughts?

Sorry for the long post, and thanks in advance.