Check engine light is still on?

I have a 2002 Honda Civic. I got gas this past Friday morning and everything was fine. Then I was driving yesterday (Saturday) afternoon and my check engine light came on. I called my Dad and he said check the gas cap. I tightened the gas cap and then continued driving. My dad also checked my gas cap and tightened it for 3 clicks and took it for a drive and the light was still on. It is now Sunday and my check engine light is still on. My car is running perfectly fine there seems to be nothing else wrong with it and I'm not due for an oil change for another 3,000 miles. Could there possibly be something else wrong with my car? Is there a way that the gas cap can be overly tightened?

Take it to autozone and get a free scan to see what's wrong with it. If your engine light is still on you need to see what codes their are to get an idea of what's wrong.

So you want us to guess which of the possible 2,000 trouble codes triggered YOUR check engine light. Trouble codes are your friends. Get yours read and then start checking the possibilities. Not the other way around.

No, you can't over tighten the gas cap. Drive the car a couple of more driving cycles to see if the light will go off. If it does not try disconnecting the negative battery cable for 5 minutes. That may or may not reset the light. If it does not or does but the light comes back on, then drive to any auto parts store where they will scan the ECU and retrieve the code that has been set. Know that the code will only tell you what part is being effected not necessarily the defective part. To determine that takes some diagnostic skills and training. BTW, this has nothing to do with when to change the oil. The light is on because the ECU has detected a problem with the emissions system.

FIRST SCAN THE CODES (AS KY-Clay said). In California, it is illegal for Autozone (or any other parts store) to scan codes because it was ruled that they don't have mechanical expertise. Depending on your state, you may have to get it scanned at a mechanic (some mechanics scan for free). You might consider buying a scanning tool, yourself; they cost about $100, and are available at car parts stores. But, likely you won't use it very often.

I agree with Stpaulguy, there are a myriad of reasons for the engine light to turn on.

Sometimes, after you fix a problem, the trouble light still doesn't go off. In that case, remove the negative battery cable for at least 10 seconds (I'd give it about two minutes, just to make sure). This resets your engine light. It also resets your clock (so you won't know what time it is until you set the correct time), and it resets your electronic ignition computer, so your electronic ignition has to relearn the best settings for your car (it will run rough until it self-adjusts).

Why remove just the black battery (negative) cable? Because only one cable has to be removed to break the circuit (disconnecting the battery from your car). Your wrench might slip and hit ground (so not a good idea remove the red (positive) cable first.

The loose gas cap pretty well tells the story. The next time the OBDII system runs a pressure test on the evap system it will pass and the light will go off, or it can be reset with a code scanner or reader. The drive cycle in the source looks pretty official and should make the system run the test.

Can't overtighten maybe you got bad gas and your o2 sensor thinks its lean burning even after you fix the problem you gotta reset it try unhooking your battery for 10 seconds reset your computer