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Old 05-18-2010, 11:22 PM
ramHD ramHD is offline
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Join Date: May 2010
Location: Grand Island,NY
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Vehicle: 2006 Ram 2500
Trim Level: SLT
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Engine: 2003-2008 345ci (5.7L) Hemi V8 345hp 375lb/ft
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PO420? that should be a cat converter efficiency code. your converter is not working, or there is an issue with the downstream O2 sensor. some aftermarket cats just dont cut it as far as being able to store the same amount of O2 as the OE cats do. also I have seen people install the wrong O2 sensor in the down stream (after cat) position. can cause all kind or running and driveability issues. the other weird thing I have seen is a problem with the trans solinoid packs going bad and causing the computer to think the downstream O2 is shorted.
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