i have been working on a friends 98 accord 2.3vtec its getting these codes
1 p0171--fuel trim malfunction
2 p0171--system too lean bank 1

i have been all over this car i cant seem to fine out what it is
here's what i have done new fuel pump new- fuel pressure regulator new plugs wires i was going to change the filter but it dont have one witch seem odd to me but anyway you have any ideals ?a few people i have talk to said it might be an 02 sensor but wouldn't it throw its own code ?

 

bump anyone ??

 

Usually the Mass Air Flow sensor just needs to be cleaned.

http://www.obd-codes.com/troub...r.php

I recently cleaned my dad's Toyota MAF sensor, and it fixed the problem. Car ran better after that.

 

6th gen Accods have MAP sensors, not MAF sensors, but I suppose the same thing would apply.

 

as far as i know all accords have maps but i never heard of a map being dirty i did try searching but didnt find anything even google and nothing just found out that alot of people have the same problem

 

I would start by replacing the o2 sensor. Most likely its reading slow. There was a bulletin about the fuel pressure regulator going bad but you already replaced that. I have seen the o2 sensor get lazy and read wrong causing the code. Usually the computer will try and compensate the fuel injector duration to try and fix a bad o2 sensor reading and it causes this code.