The problem I can't solve 5.7 vortec

[West]

Hello everyone,

I have a problem that is infuriating me, I would be very grateful if you could help me.

My 1997 Tahoe Sport, P0300 (then I realized p0305 and p0307), and p0172 and p0175. And it starts hard.
The vehicle runs with an incredibly rich mixture. The exhaust is black, and when I load the gas, it throws black smoke.
When stopping at lights, it shakes a lot.

Only spark plug 5 and spark plug 7 have carbon buildup.

Thank you in advance for your help.

 

[GoToGuy]

Look up the codes, you can do that. Put that info in your post. When last complete tuneup? How old are O2 sensors?
Those are basics.

 

[West]

Look up the codes, you can do that. Put that info in your post. When last complete tuneup? How old are O2 sensors?
Those are basics.

Thank you for the answer. I have attached the error codes.
O2 sensors are new

 

[Astro]

You can check to see if your 02 sensors are working properly with a scan tool. The upstream Bank 1/Bank2 sensor 1 control your A/F mixture.

If you look at the voltages on your Bank 1/Bank2 sensor 1 while idling, they should be alternating roughly between .1 volts to .9 volts. Just up and down.

Could be other problems as well, but like GoToGuy said, start with the basics.

 

[Orpedcrow]

What all have you inspected, tested or replaced?

 

[West]

Thank you for the answers, I live in another country. There may be delays due to the time difference.

first I will check the O2 sensor voltage values and I will let you know