I can't find the problem. DTC code 0210 (fuel injector left bank:Lean.) I just replace my front o2 sensor that's not the problem. Now I'm in the process of changing the fuel filter ( If i can get the hose off). What else should I check.

 

How does the car run? It's usually a good idea to replace the 02's as a pair. Make sure there are no vacuum leaks. Check all hoses, if you have a different intake check all the hoses going to it.

 

DTC 0210

Diagnostic Trouble Code 0210 points to a problem with the fuel injection system.

When the engine management system is running in closed-loop mode the Engine Control Unit (the computer) makes continual adjustments tomaintain the air-fuel ratio near the ideal point. To achieve this it relies on signals from many sensors includingthe Mass Air Flow Sensor and the Oxygen Sensors.

This malfunction is detected when the ECM finds that it cannot properly control the air/fuel mixture, and the
mixture is too lean (too much air). DTC 0210 indicates this problem exists on the left bank (the front bank,
cylinders 2, 4, and 6). Possible causes include ...

- Intake air leaks
- Front Oxygen Sensor
- one or more fuel injectors on the front bank
- exhaust gas leaks
- incorrect fuel pressure
- lack of fuel
- Mass Air Flow Sensor

 

The car is running fine I feel no performance loss. The only problem is the idle is a little rough.

 

From my expeience a lean code and a rough idle is usually one of three things.
1-bad injector
2-air leak
3-ignition problem (although this will usually through a misfire code, a faulty plug or coil could cause the computer to through a lean code if it's partially fireing)
In my opinion, it's probably a bad injector. I would replace all 3 on that bank. Just make sure there are no vacuum leaks first.
BTW, how many miles on your car?