p0420

  1. R

    HELP!PLEASE, P0420 Code!

    Hey everyone, brand new to this, thanks in advance for any help. Have a 2000 Yukon, 4.8L. Awesome vehicle, bought it brand new in 2000, wanted the cargo doors instead of the tailgate so had to special order it. It has 242K miles on it and it looks and runs like the day I picked it up from the...
  2. M

    I've searched and searched the threads please help me?!?!?

    I bought a 2000 Tahoe w/ 5.3 ran it for about a month, did a tune up, plugs, wires, oil ect. I also put on a cold air kit, and flowmaster exhaust. I'm now pulling a p0420 code. I am new to the mechanic side and learning as I go. I know what the code is, so I did a diagnostic pull and am...
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