Why does my husbands car go in reverse when its in drive

Question

car is ford explorer 1994 v6, had code tested, codes that showed up are: p0320, p0153, p1151, p0171

Answer 1

P0320  Ignition  / Distributor engine speed input circuit malfunction

P0153 02 sensor slow reponse (bank 1 sensor 1)

P1151 Lack of H20S switch (indicated lean)

P0171 Fuel system lean bank 1

Vacuum leaks are some of the main reason a vehicle engine management goes lean. Any vacuum leak that gets ast the MAF (mass air flow) is considred false air and will give a lean condition. Check for vacuum leaks especially at the PCV hose for rupture or torn hose. As for the car going in reverse when it is suppose to be in drive is caused by the gear selector cable breaking loose at the steering column.this needs to be secured. By the way what you listed as vehicle year is OBD 1 year.