P0171 and P0174

I have a 2002 Ford Ranger - 4.0 L with 67,000 miles. Keep getting the codes P0170 and P0174 fuel banks too lean. However, engine does not run rough at all, and no hard starts. Thought that it may be clogged fuel injectors, but that was not the problem. Now thinking that it may be sensors. Looking for some suggestions, or a way of determining the problem. Also, started feeling a steady thump from the front end while driving. Can feel it slightly in the steering wheel. It does not seem to speed up with acceleration. Checked the u-joints, and they seem to be good, a little play but not much. The tires have less than 8,000 miles, and I am going to have them rotated, balanced, and aligned. but if that does not help, any suggestions on this problem as well. I could use any help on these issues and definitely appreciate your time with your responses. Thanks.