Recently, when sitting at traffic lights in my 2000 Hyundai Elantra, I've noticed the idle dropping ever so slightly. Usually, it runs at about 800-700 RPMs, but it was dropping about 100 RPMs to 700-600. The drops were small and random, so I just shrugged them off thinking I might need a tune-up soon.
Recently, since fall has arrived, I've been using less A/C and more windows. Just yesterday, when sitting in a parking lot after lunch, I discovered a pattern.
When I shut the A/C off, I no longer saw the idle drop. Just out of curiosity, I tried pushing the up button for the windows (even though they were already up.) The idle dropped. Then I let go and the idle returned to normal. A/C on, idle dropped. A/C off, normal.
Could this be something related to my electrical system or am I way off base here? I only know the basics about cars, so please include layman's terms with the technical stuff. ;)
Two other things I should note. Might be related, might not be...
My car's reaction to the gas pedal has also been slow lately. I know it's not a powerful car, but it used to react to the pedal very quickly. Now, it sometimes hesitates for a second or two before it kicks in.
I've also had chronic problems with light bulbs blowing out (usually the tail lights.) The mechanic would catch them during an oil change, etc., and I'd have them replaced. Within weeks, the same bulbs might blow out.
Thanks in advance!