I have a 97 Ff150 with a 4.2 engine, the check engine light came on with a code of 171 and 174, I changed the o2 sensors on both sides, the light came back on after about 20 miles, I changed the fuel filter, the light came back on after about
25 miles , I was reading a post on here, where the guy was having the same trouble, somebody told him to change the mass air flow sensor, Where is it located on the truck, and how much trouble are they to change? parts store said they are $100.oo bucks, plus exchange, so I guess they rebuilt them huh? I dont mind fixing it myself, just need a little advise, thanks