How many miles are on the car? Usually new O2 sensors nowadays fail
anywhere from 50k-70k miles. I would probably change that first since
the P0171 on most postings indicate a problem with the O2 sensor. This
doesn't necessarily mean that the O2 sensor is bad, but from the age
of the car, I would bet that is the problem.

Nick



On 23 Jan 2007 11:58:28 -0800, "herdboy24" <aherdfom@hotmail.com>
wrote:

> I have a 2002 Honda Civic EX. I am having trouble with the
>cars gas mileage and also with power. Here is what its doing: Every
>time I get to a ¼ of a tank it runs really bad. At first when I am
>starting my car it has to crank like 4 or 5 times before it will fire
>up but if I crank it once or twice and then turn it to the off position
>and then try again it will fire right up like it is suppose to. The
>other things it is doing is it will stall out on me when I try to
>accelerate and sometimes will die unless I ride the clutch. Then when I
>am just sitting at an intersection it will stutter and bog out like it
>wants to die. The catch to it is though when I am on a full tank it
>runs fine except for the bad gas mileage. I am not a mechanic by any
>means and I have taken this car to 3 different people and have gotten 3
>different answers. I am tired of wasting my money with dishonest
>people.
> The check engine light is on and it reads P0171 System Too
>Lean (bank 1), but why would I be getting this bad of gas mileage. When
>I say I am getting bad gas mileage I am getting about 200 miles to a
>tank and anyone who owns a Honda knows that's horrible. The problems
>that have been told to me are this
>
>1. That I have a crack in my exhaust manifold.
>2. I need a new fuel pump.
>3. My fuel gauge is off and maybe a bad injecter
>
> I have use some injecter cleaner on the car and still nothing
>so I am hoping some one on here might be able to help me out on
>figuring out what's going on so I can get my car back to normal
>conditions.
>
>Thanks
>Aaron