'02 Sport Trac P0171 Code

[Spleeb]

Hi Folks,
I am new to the forum and in need of help. I have an '02 Sport Trac with a P0171 Code (twice I did get a P0303). I have never had a P0174 so I am tending to believe that my "lean bank one" issue is related to something unique to the passenger side.
Problems started a while back when truck started running rough. Mechanic diagnosed faulty fuel pump and replaced it. It does run some better but still runs rough at all times (warm, cold, idle, and under load). Long Term Fuel Trim is high ~20%-25%.
I have checked for vacuum leaks and found one on PCV Valve elbow. Repaired it but no joy.
I suspect maybe a faulty fuel injector (thus the P0303). I used a piece of tube to make a stethoscope and noticed the injector on passenger side closest to firewall didn't have the healthy "tap, tap, tap" the others had. This could be my imagnination but I think it to be true.
Any ideas on other things to try in terms of determining the problem would be greatly appreciated. Sorry for the long post but I thought the more details the better. Thanks in advance.

 

[swshawaii]

http://www.explorerforum.com/forums/showthread.php?p=2364255

 

[Spleeb]

Update on P0171 and P0303 codes

I replaced injectors and intake gasket. The truck cranks easy and runs smooth. My long term fuel trim for both banks is high approximately 16%. Prior to repairs the left bank was running fine. I suspect a vacuum leak but have not been able to find one. The fuel trim got high enough to give both P0171 and P0174 codes. No other codes detected. I am scratching my head trying to find source of high fuel trims. Can anyone help? I am open to suggestions or questions. Thanks in advance.