ck eng light p071 lean bank one

[1mustangsvt]

If someone have had this problem and can help me please. I can drive the car a 100 miles get out go in a store come out and the eng will have a slight miss and the light will come on i have changed all the soft vaccume hose even the one front the throttle body it goes to the vaccume spear under the right fender i have changed all the hoses to the vaccune spear if anyone has had this problem and can help i would be very greatful for any suggestions my E-Mail address is [email protected] thanks