yes I am new here and have been looking around the site for answers. hoping this is the right place to post.
bought my son a 2000 blazer
had codes:
p0300
p0146
p0420
p1351


based on what I found I did a tune up, plugs wires cap rotor
bought the b1s3 o2 did not install due to finding the one there unplugged so plugged it back in.
found coolant sensor broke at plug area unable to plug in so replaced
replaced thermostat and flush and fill
was drivable prior
after completion of work fired up and after about 15 minutes cat was glowing. had a noticeable miss, didn't before(unburnt fuel reaching cat?)
could it be as simple as the after cat o2 sensor needs replaced
I stopped due to being a long day and exhaust was hot.
I did not address p1351 due to the miss on po300, figured likely related.
I do not have a scanner.
any help be great
thanks

 

The B1S3 sensor has no impact on fuel delivery. As such, it could not cause an over fueling issue. P0146 was likely set due to the disconnected sensor.

P0300 & P1351 are most likely related and a misfire if left alone for a prolonged period of time, it can cause an already old catalytic converter to plug up which is what you have on your hands now based on the P0420 code and the fact that it is glowing. At this point, the catalytic converter will need to be replaced.

To be sure that you do not have any other problems that can cause over fueling, I would recommend that you run through the fuel pressure test procedure found in the Tech Article (DIY) section.

You can find the trouble code descriptions for each of these codes in the OBD2 Trouble Code section.

 

sorry forgot to mention cat replaced 2 weeks ago due to seller saying it needed replaced

 

Keep in mind that DTC's, (Diagnostic Trouble Codes) must be diagnosed and the problem repaired, in the order they are retrieved. Any DTC's after the first one may be caused by the first one. After each repair, DTC's must be cleared and a General Motors Driving Cycle must be performed. If the check engine light comes on before, during, or after the drive cycle, repeat the steps for the DTC that was set, starting with the first one.

If P0300 was your first DTC retrieved, that one must be repaired before doing anything else.

Edit: A glowing or restricted catalytic converter is a symptom of another problem, not the root cause. For example: If a P0300 is not repaired, it will eventually overheat the converter and destroy it.

 

ok so went out and looked before work found two spark plug wires crossed, that would be a miss and unburnt fuel. guess when I get another chance to work on it ill be crossing fingers that got it.

 

Common mistake to transpose wires for #1 & #3 plugs on the cap. That will definitely cause the converter to glow, and set the P0300!

 

now just to clear codes drive and check see where im at