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P0420 code... great

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Old Aug 6, 2007 | 11:35 AM
  #1  
GStam66's Avatar
GStam66
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Default P0420 code... great

Service engine light came on and i got that code 2 nights ago, autozone scanner says catalyst on bank 1 is below threshold levels.They narrowed (haha) it down to a bad cat, faulty o2, misfire (?),or oil leaking into the combustion chamber (??). My friends say its the pypes catted X we put on my car. Went from 4 cats to 2 hiflows. But we did that a week ago, and NOW it throws the code?

Anyway, im assumin to just get MIL eliminators? Can i do any damage to the car if i just keep driving around the way it is for a few more days?
Old Aug 6, 2007 | 12:56 PM
  #2  
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Default RE: P0420 code... great

The high flow cats can really screw with your rear O2 sensors, they don't burn off as much crap and gets the sensors all gunky and not working right. If you have a tuner just turn off your rear O2's, if not then get MILs.
Old Aug 6, 2007 | 01:18 PM
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Default RE: P0420 code... great

I didn't have to do anything with my 02 sensors when I installed my bbk catted X.
Old Aug 6, 2007 | 03:29 PM
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Default RE: P0420 code... great

you probably only need to get some mil eliminators or turn off the aft o2 sensors. when i did my x-pipe, the light didn't come on until 2 weeks after
Old Aug 6, 2007 | 07:19 PM
  #5  
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Default RE: P0420 code... great

Isnt that strange how they sometimes take so long to come on. same stuff happened with mine. Just fork out for the mil's. Easiest thing to do. Get under the car, unplug, unplug, plug in BAM. Just like that. I have heard that the check engine light pulls timing and fuel but kinda doubt that. I think its just a sales pitch. Might as well just buy the mils.
Old Aug 6, 2007 | 07:32 PM
  #6  
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Default RE: P0420 code... great

i have a similar prob but i just bought a tuner and awaiting its arrival, do you lose any hp when the service enigne light comes on? kinda like the traction control deal..
Old Aug 6, 2007 | 11:04 PM
  #7  
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Default RE: P0420 code... great

Ive had that code for probably 9 months now. Though im running an O/R pipe and im too cheap to go buy MILs or a tuner
Old Aug 7, 2007 | 10:12 AM
  #8  
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Default RE: P0420 code... great

i have that code but its because my cats are bad they hang to low and i messed them up at mustang week scraping them entering a parking lot, ive been deleting the code since i think ill just get a new midpipe
Old Aug 7, 2007 | 10:23 AM
  #9  
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Default RE: P0420 code... great

Will the car still pass inspection with the mil's on? Can the mech's computer bypass em and see that they have been tampered with or something?
Old Aug 7, 2007 | 10:38 AM
  #10  
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Default RE: P0420 code... great

ORIGINAL: OzzDOA

The high flow cats can really screw with your rear O2 sensors, they don't burn off as much crap and gets the sensors all gunky and not working right. If you have a tuner just turn off your rear O2's, if not then get MILs.
I have a Pypes X-pipe with high flow cats on my car for 10 months now..no problems or codes. Of course I also bought all new O2 sensors when I did it. The old ones had about 103K on them. I've got 116K on the car now. Unless you're running a catless X there's no reason to remove the rear O2's. I hear of people having more problems doing that, than just leaving well enough alone.



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