Hi everyone, O have a 2000 Chevy Silverado 5.3L Z71 with a check engine light on that keeps coming back.

So far I have replaced the knock sensors 3 times with wires. Replaced the manifold gasket(metal ring) replaced the EGR valve(whole kit) and all four 02 sensors.

It did show bank 1 after changing out 02 sensor but it went off after the truck sat idling for 20 min. But came right back after driving 9 miles.

I am very frustrated as it didn't pass emissions last 9ct( last emussion needed) pay my taxes on it but don't have a 2025 tag sticker and need to use the truck for camping th8s weekend.

what could possibly be the problem? I love this truck as it runs strong but dang it its now driving me crazy and broke trying to find the check engine light problem!

Any ideas what it could be?

Thanks in advance for any possible suggestions not yet thought of.

 

What are codes that you are getting?

 

As oldchevy asked, what codes are you getting? Without knowing what the Diagnostic Trouble Codes (DTCs) are from the OBDII system, you will be shooting in the dark and wasting money.

One thing to remember regarding DTCs. They never ever tell one that a given part is defective, going bad, etc. A DTC tells one that there is a problem with a given circuit or system. Hence a DTC related to the bank 1 O2 sensor could that there is a wiring problem, a vacuum problem, a fuel problem, a bad sensor or a handful of other problems.

Once you know what DTCs are present, then you have a starting point to diagnose what the problem is. If you are lucky, it could be a bad ground connection or a damaged electrical connector.

If you are going to do your own maintenance and repairs, then you really need to purchase a decent OBDII code reader/live data scanner of your very own. Notice I said "decent" and not expensive. My favorite code reader/live data scanner costs under $25.00 and it allows me to read and clear DTCs, monitor several engine/emissions systems simultaneously, and to store the data from the various sensors I monitor for offline analysis on a computer. I use a Bluetooth dongle from Amazon and the Torque Pro app from the Google Play store. I use them in conjunction with my Android device.

Here is the link for the Bluetooth dongle:
The Torque Pro App has a onetime registration fee of $5.00.

Good Luck!