2004 Jeep Grand Cherokee P0420 and p0325

2004 JEEP GRAND CHEROKEE
140,000 MILES • 4.7L • V8 • 2WD • AUTOMATIC
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GREENCHEVYMALIBU
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STFT B1 -10.9%
LTFT B1 7.8%
STFT B2 -4.7%
LTFT B2 6.3%

Engine rpm 1472
Vehicle speed 40
ECT 210.2
MAP(inHg) 10.9

Knock sensor code doesn't always trigger.

I have a live data scanner. What should I look for?
Apr 17, 2015 at 7:12 AM
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HMAC300
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see pic for causes but with the converter being bad 420 code that may set it off as well. converter probably needs to be replaced.
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Apr 17, 2015 at 7:34 AM
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GREENCHEVYMALIBU
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would it better to replace both pre cats? then just one?
Apr 17, 2015 at 8:33 AM
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GREENCHEVYMALIBU
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Could the bad cat be causing the knock sensor code?
Apr 17, 2015 at 10:40 AM
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HMAC300
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teh cat system may be in one piece so both get replaced at same time. and that is what I ameant when I said the 420 code may set the other code.
Apr 17, 2015 at 12:06 PM