o2 sensors

  1. G

    2000 4.0L Front Cats and O2 Sensors

    I am fighting my ANNUAL O2 sensor/CAT code battle with the Inspection shop. Last year the shop replaced an O2 sensor and passed the Jeep, but the light came back one three days later. This year they are suggesting that I replace the front Cats??? Anyway wanted to get some thoughts? Do I...
  2. KCsTJ

    Pre-cats and y-exhaust pipe repair (solved)

    I am troubleshooting a p0431 code on my 05 Sport, "warm-up catalyst efficiency below threshold, bank 2". I have ordered both NTK o2 upstream sensors which may correct the problem. However I plan to also replace the Pre cats as PM cuz it has 101k. I plan to unbolt the 2 pipes connected to the...
  3. KCsTJ

    Diagnostic Code 51

    I randomly check for engine codes and last week a DTC 51 pops up on my 97 SE. 51- Oxygen sensor - lean condition indicated I just love these vague codes...aarg Anyone have ideas, please post, headed to the tj right now to check 02 connections, and look for vacuum leaks It seems to run fine...
  4. R

    Check engine light and O2 sensors

    I own a 2005 Jeep Wrangler Unlimited LJ with 100k miles. The jeep runs great, but the check engine light has been on for several years now. The mechanic says that his computer codes are showing that all the o2 sensors are bad. However, he doesn't think that is the case. He thinks it's probably...
  5. L

    O2 sensor issues and code P0133

    O2 Sensor Problems My check engine light came on a while ago code p0331 and I changed both upstream o2 sensors The light went off for about 2 weeks and then came on again same code P0133 Then the light went off again after a few days and now it is on again Anyone have this issue? Tks
  6. jodomcfrodo

    Replacement Catalytic Converter

    Hi all, I've been forced to get my catalytic converter fixed because I'm moving to a state with emissions testing. I've had the P0420 code for over 5 years now. Recently, I had a dealer install a new converter, but the code is still present. I think this is because the converter the dealer put...