Hey all I got a 1999 ford expedition yesterday and today I got a check engine light. The codes were P0171 and P0174 for fuel trim bank one and two condition and P0401 for EGR system fault (exhaust gas recirculation). It seems to run really well and idled for two hours with the ac on at DMV (the check engine light was already on at this point). The original owner said he has the battery out to charge it. But now I wonder if it was to hide the codes. I need to drive cross country Can I fix these sensors after my trip? Am I screwed? Thanks in advance!