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Discussion Starter · #1 · (Edited)
The truck is a 2000 Silverado 2500 6Lwith 129,000 miles. It doesn’t seem to have the mpg or power on accel it dead when I first got it three years ago. Fuel regulator, spark plugs and spark plug wires have been replaced but I have not touched anything else other than standard maintenance.
Wheel Tire Automotive parking light Car Sky


I am getting intermittent codes for the following:

History:
P0140-stop lamp switch circuit
P0141-oxygen sensor heater Bank 1 sensor 2
P0157-Oxygen sensor circuit low-voltage bank 2 sensor 2
P0158-Oxygen sensor circuit high-voltage bank 2 sensor 2
P0160-Oxygen Sensor circuit, no activity detected bank 2 sensor 2
P0161-oxygen sensor heater circuit, bank 2 sensor 2
P0463-Fuel level sensor A circuit high input

Intermittent:
P0140-Oxygen sensor circuit No activity detected bank 1 sensor 2

Confirmed:
P0140-Oxygen sensor heater Bank 1 sensor 2
P0157-Oxygen sensor circuit low-voltage bank 2 sensor 2
P0158-Oxygen sensor circuit high-voltage bank 2 sensor 2
P0160-Oxygen Sensor circuit, no activity detected bank 2 sensor 2
P0161-oxygen sensor heater circuit, bank 2 sensor 2

What I have done-
I checked the fuses- all looks good there. I bought 4 new GM O2 sensors which will be here Wednesday. I plan on checking the wiring to them today.
Anything else I should focus on? Maybe Bad cats?
 

· TOTM
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Anything else I should focus on? Maybe Bad cats?
Get a subscription to the shop manual so you can properly troubleshoot each code. Firing the parts cannon is expensive with no guarantee of results. Make sure your scan tool can do whatever the troubleshooting guide requires of it.

When a cat fails, it has its own codes, the only time there is a false positive is when there is a massive exhaust leak in front of them to the heads.
 

· SilveradoSierra Guru
2004 Sierra 3500 6.0L, auto, extended cab, cab&chassis, upgraded to 4wd
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3,178 Posts
If the cat's are plugged, that will cause problems, but, like above, diagnose instead of parts cannon.

Check things like:
-fuel pressure at the rail, should be 55-62 psi, both at idle and when the engine is sped up to say, 3k rpm
-all the exhaust manifold bolts are present (they are known to break off, and can cause exhaust leaks when they do, screwing up o2 sensor readings, which then screw up how the engine is run)
 

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28 Posts
Discussion Starter · #5 ·
After you install the O2 sensors, see what comes up.

As an aside. I didn't know there were OEM wheels like that in the 8 lug pattern (6 lug is very common in that style). Those look awesome. I will have to keep an eye out for used set.
When I went to 32” tires, I didn't want to keep my 16” stock rims. I found a set of (4) 2007 GMC Sierra 2500 rims for $200. Now its hard to find a 5th to use as a spare for under $200.
 
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