sounds like your dad was under qualified to do the job and didn't do it right. i have a 97 f150 , previously had a 96 silverado ,and i am a mechanic at a shop where we work on everything. and fords, chevys all have their problems .both makes are good if you take care of them and fix them when they break (chevys are much easier to work on)
common problems with silverado and f150
ford f150 - bad about vacume leaks , o2 sensors, mass air flow and iac valves getting dirty. and dpfe sensors going out
chevrolet- staters, battery bolts and spacers, water pumps, lower intake manifold coolant leaks, and fuel pumps