My daily driver is a 2007 Kia Rondo, 2.4L 4-cyl. I bought it new and I've put 50K miles on it.

About a week ago, the Check Engine light came on. I decided it was time to own an OBDII code reader, so I went out and bought one at my FLAPS.

I hooked it up and it gave me the code P2187: System too Lean at Idle Bank 1

I presume the "Bank 1" part is the default for an inline engine.

I figured it was an anomaly and cleared the code. Within 2 days, the Check Engine Light was back on, and giving the same code. This time, I didn't clear it (so the light is still on every time I drive... much like every NYC taxi.)

I can discern absolutely no difference in the way the engine's running, sounding, or driving. I suspect the weather may be a factor - both times the light came on, it was a fairly cold morning. I'd be more concerned if the diagnostic code implicated a particular faulty part, such as an O2 sensor.

Should I worry? Should I clear the code? Should I get to a dealership soon, considering there's a 10yr/100Kmi powertrain warranty?

All of my cars have the cel light on. When it is time for inspection I get around to fixing them. Generally if a car has a tendancy for a problem the information and solution is readily available using a search engine.

In your case the manufacturer is on the hook both because of the warranty and because they are required to fix any emmission issues up to a certain number of years and miles. (6 years 80K perhaps not sure since my cars are too old or too many miles).

I'd guess a bad o2 sensor, vacum leak, or bad air temp sensor, but you never know. If you can lose the use of the car then take it in. If not use your best judgement and/or wait until you can. If you start throwing other codes, like misfires, etc. on top of this I'd stop using it as an actual overlean condition can be a fairly serious issue.

Definately take it in since its still under warranty, call ahead if they have rental available for you.

Being obd 2, you probably have multiple o2 sensors, usually 2 befor the cat and one after. Since it happens on cold mornings, I'm guessing the heater element is not up to snuff in one of the o2s before the cat.

Take it in before next smog check.

When I got the same code on a Ford minivan years ago I assumed the O2 sensors and the EGR (well I was getting those codes also).

$300+ in parts and no change in anything. Turned out to be a vacuum leak at a 90 degree elbow on the manifold. Grabbed a piece of fuel hose laying around the floor of the garage and instantly it ran better and the codes cleared, never to return again.

A can of carb cleaner with the thin tube attached will help you find vacuum leaks. Spray around ALL joints, seals and seams in the intake system. If the rpm momentarily pick-up, there is a leak. Good Luck!!

Easy thing to do, call your local dealer and explain the problem and see what they say about emissions coverage for your car. Worst thing to do is start throwing parts at it. Alot of codes can come up that sound very straight forward but have an underlying problem that fools the computer into setting a code for what it thinks is the problem area. If your not covered under warranty, make friends with one of the dealer smog/drivability techs and supply enough beer to get it fixed.

Go Here:
http://www.kiatechinfo.com/
and sign up.
It is free and you get all the Kia repair info they have.
This is the same info they provide the dealerships.
You can look up the code and test/repair procedures
Jim

With most of these suggestions. My '96 Mustang never threw a code until just recently, then I got a whole mess of them. I went against what I've always learned - replace the cheap stuff first and work your way up. Instead I went through a MAF sensor, IAC valve, EGR, etc. Of course I totally missed the vaccuum hose leading to the intake, recycling crank case vapors. I would always check emissions stuff first anyway - its very possible, like in my case that you bumped a hose loose when changing oil or another simple task.

The other route, checking the forums is VERY useful. Most of the time when a car throws a code like that, it has happened to others and is a common problem. Really cuts down on the headaches once you have some idea where to start looking.

Finally, since the car is still under warranty, I would just take it back. I'll never buy a new car, having worked at a dealership in college. But, since you already paid for the service, you might as well use it! Good luck.

I too would probably check the vacuum hoses, but.....when one of my cars threw a lean code like yours, it turned out to be a clogged fuel filter evidenced by all the crap that came out of it.

Andys