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  • 2005 - 2009 Specific Tech

Error codes (p0420) - possibilities?

  • Thread starter Thread starter matty
  • Start date Start date Nov 16, 2009
M

matty

Member
Mar 23, 2001
101
0
16
Edmonton, Canada
Nov 16, 2009
#1
  • Nov 16, 2009
  • #1
I have a 2006 Mustang GT and as of late it’s been throwing codes (P0420 and P0430 - catalyst efficiency below threshold both bank 1 and 2). I had it into the dealer (since it was initially hard to cold start and would produce smoke), the dealer said it was due to my AFE Stage 2 intake and oil filter which was over oiled and as such some of the oil had transferred onto the MAF sensor. They cleaned it and I had the same problem again, this time I purchased the AFE dry filter, sensor cleaner & throttle body cleaner and went to it on my own and cleaned everything out before reinstalling the dry filter, clearing the codes (oh btw I have an Xcal with Brenspeed tunes). Upon taking everything apart I noticed that the rubber seal between the throttle body and the intake had been significantly over tightened and over time had developed a crack. Could this be the culprit of the check engine light, rougher/higher idle etc.)? I’ve looked for a part number but haven’t had any luck searching for throttle body gasket (and TB seal), does anyone know what the part number is?<o></o>
Thanks,<o></o>
Matt<o></o>
 
C

COBESGT

Member
Oct 19, 2004
231
0
16
Dubuque, Iowa
Nov 16, 2009
#2
  • Nov 16, 2009
  • #2
Do you have an Off Road H/X Pipe installed on your car? If you do, I think these codes can come up if you don't get the Rear O2's turned off in your computer program. If you don't, I think I remember hearing that air leaks on the Intake, MAF, couplings, etc, can create DTC's as well.
 
M

matty

Member
Mar 23, 2001
101
0
16
Edmonton, Canada
Nov 16, 2009
#3
  • Nov 16, 2009
  • #3
Thanks for the quick reply. The exhaust is all stock.
Matt
 

SpartaPerformance

10 Year Member
Nov 5, 2006
2,517
61
89
Long Island NY
Nov 17, 2009
#4
  • Nov 17, 2009
  • #4
Yes. If the engine is taking in unemetered air then the o2's will read more oxygen in the exhaust and set off that code.
 
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