Hard to say specifically what to look for... You need to look at everything. Ask to see service records... Run a carfax... pull engine codes, or have a knowledgable mechanic check it out... Check for rust, bondo, missing parts, condition of belts, hoses, wiring harness, etc. If it is an AOD(E) check the condition of the tranny fluid. And then if everything checks out and you are satisfied with the car, offer $2K... Save the remaining $900 for the repairs (there will be repairs).