kddesai98

Since couple months I am struggling to correct "Service Engine Soon" problem with my Nissan Sentra GXE 2000. I am located in IL. Since 6 months or so, the SES light was ON. Emission Test requires OBD II clearance, therefore I had to visit the local mechanic to correct the problem. He diagnosed it as P0171 (system too lean bank#1) code. I ended up changing one O2 sensor out of 4, the code still came back after a few miles drive. I ended up changing another O2 sensor for the same pair. Again light came up. Did fuel injection system cleaning too, no luck. I even consulted another mechanic too for 2nd opinion. Now, the mechanic is telling me, i have to change the ECM board (the voltage is significantly low (0.06 or so as I recall) and so scanner shows a lot of fluctuation). So, I am thinking about it and asking for your advice whether that's the real cause & solution? Since couple days, I've noticed lack of power too. I had to heat up the car for 5 min. thenonly, it drives OK. I feel little lack of power with a stop-n-go driving.
Any suggestions? I am little desperate now, the EmissionTest has to be cleared this month, otherwise they may suspend my license.
Will ECM replacement fix the problem permanently?
Thanks very much in advance.
KD