Need help with a code DTC PO420
Thread Starter
Racer
Joined: Sep 2003
Posts: 275
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From: West Monroe La.
Need help with a code DTC PO420
My 95 six speed is showing a code PO420, low oxygen capacity. Some time back I installed a set of crane 1.6 full roller rocker arms and springs. I screwed up and swapped the #2 and #4 spark plug wires, and it took me a week to find my screw up. During that time I reset the valve lash about five times, and looked everywhere but the obvious. When I finally found the problem, I had fouled the two plugs. I replaced them and still had a problem. It was the two sensors on that side, both fouled badly. I replaced them, and cleared the code, and it ran fine. I recently put a Force II Flowmaster cat back system on it, and checked the comp. codes after I had run it for about a week. That's when I found the PO420 code.
My question is could the converter have fouled so badly when I was running it with the plug wires swapped, that it has now gone bad? I have checked the system for leaks and found none. I hate to put a new cat on it only to have it not solve my problem. Any help would be appreciated. Thanks, Tom
My question is could the converter have fouled so badly when I was running it with the plug wires swapped, that it has now gone bad? I have checked the system for leaks and found none. I hate to put a new cat on it only to have it not solve my problem. Any help would be appreciated. Thanks, Tom
