mjjstang

so I figure ill ask here since I dont know any good ford taurus sites, my dads 2000 taurus is acting up. rpms and such are going a little astray, well I put obdII scanner on and it said "system too lean", this would make a lot of sense BUT, fuel pump, filter, maf, egr shit, etc has been replaced, yah my dad spent 600 bux on a maf, no matter what I tell him he wont let me work on it. but anyway im tryin to help him, so does anyone know the problem, he says the shop probably wont warrent the work anymore, I swear its only been like 8 months or so, but yah any help would be sweet.