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P0430 Code 100 miles after resonator delete, and higher octane fuel

malibu7899

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Good morning, everyone. So, like it says in title i bought my Mustang GT used with 11,500 miles on it. So i do not know what type of fuel the previous owner used during owner ship. The best fuel I have available to me is 91 Non ethanol which I have used since buying and car currently sits at 13,600 miles. In the last 100 miles I installed Steeda H pipe resonator delete. and I went online and checked with a fuel blend site to see what I could do to reach 93 octane for a tank and just see if the car likes it. So I added 2 gallons of 110 fuel and 14 gallons of 91 to theoretically get me right around the 93 octane number. Now within the first 100 miles i had a p0430 code, and I thought maybe the car just hadn't adjusted maybe to the different fuel, so I cleared the code and it came back on within 30 miles. Just seeing what you guys might think. Did the fuel smoke a oxygen sensor, or is the cat starting to fail? The plan is to run the rest of the fuel out and fill back up with 91 again and see what happens before I make a appointment with the dealer. Just curious on everyones thoughts or if they have seen this. Thanks, Jason.
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malibu7899

malibu7899

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No, not at all. I had a 1/4 tank of 91. Filled 2 gallons of 110, started it and drove 150ft forward to the 91 pump and topped it off. Started it and whet on my way like normal.
 

Fender5803

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I'm thinking it might be OK with 91 oct ? Maybe drain the tank ?
 

drive_55_not

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