Thanks Night Swimmer,

Yeah, I got myself one of those scanners. I plugged it in and the code is "0171 - System to lean (Bank 1) ". As Oldeng said, this is related to the air duct. I think, I need to do further detailing on this air chamber and the duct.

thanks

I opened the air duct and took out the MAF sensor. It was dirty. I cleaned it and re-installed it. Also tightened the air filter chamber. For now, everything looks OK. I think and I need to wait and see.

thanks

I had a bad fuel filter give me an 0171 code once. Dirty injectors can also cause that.

I think what you opened was the air filter box. The air duct is the hose that connects the air filter box /MAF assembly to the engine. It's is often that hose that gives the P0171 problem. You have to inspect it very carefully for cracks.
Furthermore, you don't have to "wait and see". To clear the code(s), just leave a door open so the courtesy light is on, and disconnect the battery -ve terminal for 30 secs. or so. That drains the capacitor in the PCM, wiping out the latched codes and CEL; then re-connect the battery and you're set to re-test the car with a cleaned out trouble code memory.
You will have to reset the clock time and radio tuner memorized stations though.

You are right Oldeng. I opened the air filter box. I will take a look at the hose today. As I said before, the folded section after MAF assembly has a crack. But, I dont think it is deep enough to cause any leakage. But, I will double check.

Yeah, since I have the scanner, I erased the CEL code with it. Thanks for that instructions though. I was saying that I need to wait and see if the CEL comes up again.

Thanks

Don't kid yourself. The legal air going thru the MAF had to struggle thru the filter. The sneak air doesn't, and also is closer to the engine, so it has an easier time making mischief.
Moreover, what looks like an insignificant crack under static conditions might not be when the engine is moving on the mounts, and finally, where there's one crack you saw, there's very possibly others you didn't. Deal with that duct!