hello... i just recently purchase my 97 land rover discovery and the guy i bought it from said the check engine light was on due to a bad 02 sensor.... now i confirmed this with many other shops and i just want to know, do i replace all 4 of them or is there a specific one that always poops out? Thanks

 

Front two are the only ones that affect rthe performance off the engine, the rears turn on the code if the cats are bad. What was your code?

 

You would only need to replace the front 2 unless the back ones failed completely.
HOWEVER, 98% of all O2 codes are from the need of a tune up, that means spark plugs and spark plug wires.
Magnecor, STI or Kingsbourne plug wires only or you will have problems.

 

Having just gone through this, I can tell you that the codes will tell you which O2 sensor needs to be changed.
Have fun changing the front ones....

 

thanks guy this was real help...

 

the code is p1179.... and when i bought the car it had a knockoff k&n air filter from auto zone on it instead of the stock air intake.... so i bought the stock air intake thinking that was the problem but it wasnt... i need to get it smogged this month and california is so damn strict... anybody got a solution?

 

Move out of Cali...

Amazon tends to have very good prices on o2 sensors and often free shipping.

 

try cleaning the maf. p1179 is often a maf code. search maf or cleaning maf.


after you clean the mass airflow sensor get the code reset and see if it comes back.

 

P1179 Maximum Negative AMFR Correction Fault

If you had a KN filter on it, I wonder if it fouled the MAF sensor.

 

it might of.... idk what to do.... get a new maf sensor or 02 sensors....