I think my CEL was from a loose gas cap problem, when I tighten the cap, its kind of rough and not a smooth turn. But I don't think I have a bad gas cap because when I remove the gas cap, I hear the pressure releasing from inside the tank.

 

You won't know for sure till you pull the code.
It may be a bad gas cap, but some have found that it's the filler neck.
Release of pressure when sometimes removing the gas cap is not unusual. This is not a definitive sign that something is wrong.

PULL THE CODE.

 

[QUOTE=xviper,Feb 2 2006, 10:26 AM] You won't know for sure till you pull the code.
It may be a bad gas cap, but some have found that it's the filler neck.
Release of pressure when sometimes removing the gas cap is not unusual.

 

I had it happen to me once, but it was because I did not put the cap back on properly. My mistake. It took three or four drives for it to go out.

 

= gas cap (most likely) or filler neck or other leak in gas tank.

 

It could be a loose gas cap caused by a deformed filler neck. My '02 has always had the deformed filler neck issue, which requires me to tighten the gas cap in a certain way to ensure a tight seal. See this thread:

https://www.s2ki.com/forums/index.php?showtopic=175774

The method described by "Heartless" has worked great for me as I'm too lazy to get the real problem, a deformed filler neck, fixed.

 

The cas cap on my car starts to "rattle" when it's tight enough.
As a slip-clutch (sorry if thats not the correct word)
I can't make it go tighter even if i wanted to.

Is that the same for US cars?

 

Yes.

 

People who have the loose gas cap problem also reported a strong smelling gas, but I don't smell any gas. CEL just came back on, I guess I'll be visiting the dealership to see if its a purge valve, gas cap, fuel filler, or other numerous faults in the fuel tank.

 

ALL 2002 S2000s suffer from this problem, it just takes a while for it to show up. It can temporarily be solved by getting a new gas cap, but it can only be permanently solved by replacing the fuel filler tube. I did, and it has been perfect ever since.