I'm not all that worried, but SHOULD I BE?
 

Filled up the tank today (with the appropriate octane, since I'm certain someone will ask), drove around a bit, ran out to pick up lunch, etc, etc...everything way completely cool.

Driving home from work tonight, moving at a pretty brisk pace on the highway, I throw a Service Engine Soon light. Pull over, four-ways, etc. Pop the hood, no smoke, no flames, nothing obviously wrong. Checked the hose everyone seems to have popped off at some point...looks cool. Open the fuel fill cap (seemed to be on tight, but who knows), put it back on, get back in, and cycle the ignition.

Light's still on. Cycle again...still got the light.

Merged back onto the highway, drove about 5 miles home, parked, went inside, and came back out about 5 minutes later.

Cycled the ignition once or twice more, and now the light's gone.

I've driven the car maybe 20 miles since then. No obvious issues...it was pulling hard and shifting OK while I was out this evening.

My instinct suggests this was simply a gas cap issue, but the owner's manual makes it sound like the light shouldn't take that long to clear if it's an evap sensor, and I don't want to guess wrong and cost myself in the long run.

THOUGHTS?

I would go in and get it scanned anyways. Just because the light goes out doesnt mean there isnt a code stored, then you will know for sure. If it was a fault that risked engine damage I would assume the OBD2 system would put the car into "limp mode" and you would surely notice a driving issue when that happend.

Shouldnt you still have warranty left anyway?

mods?

I'm betting fuel cap.

I'm betting fuel cap also. Sometime it can be threaded wrong and seem tight without being totally sealed. By taking it off a putting it back on, you probably fixed that part. Where are you in PA? I can check the code for you.

Are you modded?

Mine is one all the time cause of no cats.

the dealer scantool (much like other people have said) can still see codes that it has thrown in the past, even if they are not currently on. for spending <30K you might as well at least drive to the dealer to check

Yah sometimes it takes a couple cycles or km's to convince the ECU that the vacuum leak is gone (from untightened gas cap). Took about 30km's on my truck when it happened. Get a scan tool and you can avoid this worrying stage and know right away if something is drastically wrong.

ive had this "service light" pop up on me when I was at 2200 miles... I pulled over popped the hood and nothing... Turned the car back on, everything seems fine, few minutes later transmission overheating popped. I checked the fluids and they were all topped off too. I went to the dealer to get it checked out and the sensors somehow got screwed and they replaced them for free.

It might be an actual issue or it could be your sensors smoked some crack and just messing with you. Either way, get it checked out. Btw, if you have mods even as simple as an aftermarket intake they might try to screw you over the repair and say "you put an intake, oh thats what caused the problem so you are gonna pay for it", just watch out for that. Im lucky as my dealers' maintenance manager owns an evo and he is a trustworthy guy, he helped me a lot when I got the car so he wont screw me over with things like that but other dealers might

I'm completely stock. I'll drive it tonight, and if I see anything even remotely unusual, I'll get it to a dealer as soon as I can manage.

Id invest a CEL reader/clearer. I randomly toss o2 trim level / low circuit all the time. Sometimes 1 or twice a month and sometimes 0 for months at a time...

I find these ECU's are quiet picky.

id get an accesport which is also a CEL reader/clearer, but anyway, good luck with your car dude i konw it sucks having something like this in theback of your head. i know my day is never good when i know that my baby in the driveway is sick

You can't just cycle the key to get the check engine light to go off. Most faults need two drive cycles with no fault for it to go off, if it's a fault that will go off itself. You have to have the car running for the tests to activate, and then also be under certain conditions for some to run. Just get it checked, or find someone with an AP or go to an AutoZone or something to see what the code was.

yup, it might worth u to check.

Bought a OBDII reader. I figure it'll save me some effort in the long run, and it wasn't that expensive. Will share more info once it arrives.