engine codes

hello i have a 1999 ford explorer my codes are P1071 P1074 P1112 i replaced numerous parts can not figure out what is wrong

Welcome to the forum!

To prevent us from spending a bunch of time suggesting you look at parts that you've already replaced, please provide the details as to what all "numerous parts" you've replaced. Also, do you have any symptoms besides the diagnostic codes such as a rough idle, lack of power, poorer than usual fuel economy? Also, which engine do you have?

-Rod

Welcome to the forum!

To prevent us from spending a bunch of time suggesting you look at parts that you've already replaced, please provide the details as to what all "numerous parts" you've replaced. Also, do you have any symptoms besides the diagnostic codes such as a rough idle, lack of power, poorer than usual fuel economy? Also, which engine do you have?

-Rod

parts i have replaced MAF sensor IAC sensor all 3 OXYGEN sensors all new VACUM hoses PLUGS and WIRES The truck is lacking power very bad rough idle in cold weather fuel milage is very bad engine is 4.0 vin num 8th letter is X and 10th letter is X Thank you for the help

I don't recall if the Intake Air Temperature (IAT) sensor is built in to the MAF on your '99 or not. If not, the P1112 code suggests the IAT is intermittent, which could certainly explain the poor fuel economy. Have you cleared the codes since replacing the MAF and other sensors? How about the Coolant Temperature (ECT) sensor, have you checked to see if it is within range based on temperature and resistance to ground?

-Rod

Are the codes actually P1071 and P1074? Could they be P0171 and P0174? These are lean codes and will cause the running problems. If it is a 4.0 L, the intake gaskets are a likely suspect.

I agree with Way2Old on the first two listed codes. I just checked the factory service manual for 1998 and 2000, neither list a P1071 or P1074.

-Rod