Can any one tell me what code #'s 0171 & 0174 mean. It is for my 98 Navigator. Thank you.

 

Yeah I can tell you but it's gonna cost ya $5 bucks a code!!! Just kidding...LOL.

171= system to lean ( bank 1)
174= system to lean ( bank 2)

Now your left wondering what the heck that means. I can not tell you exactly what it means but I can tell you what I know. Lean is not good, lean causes your motor to run hot and cause detonation. Have you heard it pinging lately?
Possible causes can be:
clogged injectors
O2 sensor's
timing is off (shouldn't be as it's controlled by the PCM)
other fuel system problem

I suggest having a good mechanic/tech look at it. Search this site, this has come up before.

 

change fuel filter,first

 

if your engine is running lean it means there is to much fuel in the air/fuel ratio because there is an optimum ratio if it running lean expect detonation and increase engine wear,and if your running rich to much air

 

dloreanwiz,

Uncross those wires. Lean is not enough fuel and rich is too much.

Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks.

If all of these check out the next thing to check is the MAF. That should be left to a tech.

regards

Jean Marc Chartier