Hi, I searched already but it seems I have different symtoms than people have had from the past. I drive a 99 Eclipse GS which is now bone stock. When I used the scanner it said system too lean P0171 bank # 1. For the past few days I have had my CEL on. Most of the time its fine. Its only sometimes at idle it almost seems like it wants to die out. The rpm goes down to 300 sumthing. But after a few seconds it would go back up like I just started the car without tapping on the gas. And even on one occasion It didnt go back to normal so I tapped on the gas but it didnt have any affect as if I didnt tap the gas at all but it went back up a few sec later. And this morning my exhaust was spitting out wet black sut. Sorry for the long post I just wanted to give you guys all the detail. Thank you for your time!!

p0171: system adaptive fuel too lean, bank 1

no idea on this one, maybe your car is running lean and your fuel filter needs to be changed

Greetings from Germany, i just finished my move, got the clipse of the boat and on the autobahn she governs out like a dream at 135, gotta do something about that-imagine running flat out with no fear of the law-sweet!

Yea I feel ya I have the same problem now, I went to the German Mitsu dealer a few days ago I found out that your code is a fuel flow problem, you may need a fuel pressure regulator, or a fuel filter as I was told. If you see black smoke your running rich so it's not your filter, if she wants to die out on ya, you may just need a new fuel filter. good luck

BOOST!-a Tis far better to have it and not need it-than to need and not have it.

i had that 2 days ago, i'd put money on the 02 sensor being bad.

I haven't spent any money yet so I will try and go ahead with the sensor change first then. So! basically you're saying that you got rid of the cel by changing the 02 sensor, now I have 2 one on the downpipe and another after the cat should I change them both?

1998 GST Spyder Still bone stock
BOOST!-Tis far better to have it and not need it-than to need and not have it.

bank one is the first o2 sensor.

Poss o2, i would check a few things first.

Fuel pressure at static. (need to jumper relay with engine off should be 47-50psi.) I know o2 fail pretty easy but chk before you just start replacing things. Make sure no vacuum leaks, carefully with a can of carb cleaner, spray around each vacuum fitting. Do not spray the crap out of it just a little is fine. If you have a vacuum leak the idle will jump up when you spray a joint. Do not spray around the EGR...it is too hot and if you spray too much it can cause problems you do not want.

Terry