Mustang Evolution

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05torch 10-04-2009 02:25 PM

So, I just recently purchased this stang. A couple of weeks ago, it threw a CEL I think because I accidently filled up with 93. I had the codes read and it said:

P0506 Idle lower than expected
P0420 Catalyst System Bank Efficiency below Threshold - Bank No 1.
P0430 Catalyst System Bank Efficiency below Threshold - Bank No 2.

So I cleared the codes and they did not come back for a couple of weeks, I attributed it to the gas. The other day they came back. Now....

Sometimes when i am stopped it will stall several times in a row and I have to hold on the gas to keep it started. Then other times it will run fine. I have been noticing the smell of gas at idle times (running rich?).

So today I was driving along, and I made the shift from 2-3. After I depressed the clutch, the engine started revving itself. Oddly enough, my foot was not on the gas, cruise nothing was on. I put it into gear and let the clutch out and it drove itself. Very odd and scary, felt like the gas pedal was stuck, but it wasn't. After a minute or two it stopped.

I could start with the 02 sensors, which some suggested on other forums, but which 02 sensor is it?

Any other ideas?

2007STANG 10-05-2009 12:49 AM

Re: CEL/Problems
I'm thinking clean the MAF

05torch 10-05-2009 01:03 AM

Re: CEL/Problems
Do you think a dirty MAF could throw all three of those codes?

OsirisGuy 10-05-2009 01:05 AM

Re: CEL/Problems
Well first start figuring out why the idle is so low. What RPMs are you idling at? Cleaning the MAF could help.

Since you have both Bank 1 and Bank 2 codes, ones on passenger side one's the driver side. I don't know off the top of my head if it's the first set or second set but I would guess it's the set after the Cats. If I think about it hard though I change my mind to the set before the cats though.

Sorry for not really helping.

2007STANG 10-05-2009 01:07 AM

Re: CEL/Problems
it sounds like its running rich to me

OsirisGuy 10-05-2009 01:11 AM

Re: CEL/Problems
Scratch that last post (my post). The codes get thrown involving both O2 sensors. Here's some info:
OBD-II Trouble Code: P0420 Catalyst System Efficiency Below Threshold (Bank 1)

Looking at this does your car have Cats? If not that is your problem. If you do have Cats they might be bad. Did the car have to pass an emissions test?

Basically what's going on is the the Downstream sensors (second set/after Cats) are reading the same chemical emissions as the Upstream sensors (first set/before Cats).

Of course the problem could still be the O2 sensors, and might include any of them, but most likely it might be something else.

billr814 11-15-2009 07:25 PM

Re: CEL/Problems
93 octane by itself..certainly 1 tank only won't hurt your car...

11:46 AM

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