98 Ford Expedition problem code P0171 P0174

I got a 98 ford expedition and the check engine light came on and the guy at auto zone check it and the code was p0171 and po174 I think he told me to check all the hoses but I couldn't find anything so I call my father and he said it might be the fuel injecters and nowthe car engine is shaking acting like it's about to die like if I was running out of gas