Code 25 problems
 

1994 Toyota pickup. 3vze. about 7,000 on reman engine.
i'm 19 and i am no mechanic by any means so i need some help. As i was driving home last night from about a 90 mile trip the check engine light came on. the car started to shake when accelerating then fine once done accelerating. idle is a little rough as well. I pulled the code this morning (had to look up how to do that) and it is code 25 (Air/fuel ratio LEAN). So where do i go from here. I've looked on some other threads but they seem to have multiple codes as well as 25 (i.e. 25 and 71). what are the most likely reasons that this code is coming up. oxygen sensor? fuel pump? is this something that myself, not being very educated in this sort of thing could do? its my daily and i cant go with out it. also is it bad to drive it like this.
any help is appreciated.