Replaced o2 sensors on vt ss and still throws codes PO133 and PO135

[Adds_05]

Hi all, just bought an LS1 vt ss with pacemaker extractors and high flow cats.

After playing around with it for a day or so i realized the CEL globe was missing so i put one in and it threw up the engine light so got it checked and it was codes PO133 and PO135 which were o2 sensors were slow.
Mechanic put 2 new sensors in but it still throws the same codes up.

What has everyone done to fix it? seems a few people over the time have had this same issue.

What makes it more urgent is it turns out the bloke i bought it off had a defect from the EPA for exhaust and the light missing which i didnt know about until the letter turned up today.
Standard exhaust was put back on but got knocked back for globe missing.

TIA

 

[accentstencil]

I can't help but the guy you bought it of is a dishonest sleeze bag. Doesn't the mechanic have any ideas?

 

[Adds_05]

The mechanic seems to think it could be something to do with the high flow cats but he's not 100% sure

 

[accentstencil]

I just put high flow cats on without issues. Maybe you need a tune. I would say that the guy put extractors and high flow cats on and didn't bother with a tune.

 

[BlackVXGTS]

Refer to the attached. You may have a wiring problem.

 

[Pollushon]

Sensors are in front of the cats so it won't be those. Could be bad fuel pressure, vacuum leak or a bad coolant temp sensor.

 

[Craig Facey]

Just cleaned my sensors with a wire brush, sand paper and MAF cleaner and then swapped them over.... had better throttle response on a cruise straight after like some other people say but then the idiot light came on again.... at least I know now that it's the sensors and not the wiring earthing out against the BCM like some people on here report.... I noticed that the wiring clips are challenging to get to so be careful when you change them cause I can see there are a few videos on rewiring the clips on youtube so I am guessing that some people have been rough when replacing a sensor and then had to replace the sensors again before figuring out it was the wiring that a heavy handed mechanic stuffed up (Must have been a first year on his way to get a left handed spanner!)....... anyways I better be off to eBalls to order some new proper brand name O2's.....

Good luck and don't forget to post your solution cause so many people never come back to give a conclusion on their threads

 

[lout]

Good luck and don't forget to post your solution cause so many people never come back to give a conclusion on their threads

what he said