I have a problem showing both these codes. In the freeze frame data the LTFT b1 is 21.3 and the LTFT for B2 is also 21.3.
Both short term values are around 4 %.
These codes do not show up until i have driven it about 3 times.
Is it vacuum or Fuel?
The cat is rattling, could this cause it?
Thanks

 

Probably not a vacuum leak as that most likely would not show equal FT's on both banks. Probably not the converter as it is downstream of the oxygen sensors, (after the fact). If those FT readings are both positive, and the DTC's showed up simultaneously, the next step is to check fuel delivery. Low fuel pressure and or volume will cause both of those DTC's to set simultaneously, as the fuel delivery system feeds all cylinders equally, which will affect both banks equally. https://blazerforum.com/forum/2nd-ge...eakdown-88305/ Post all 4 readings, and we can help you analyze them.

 

Hello, I had added the GM injector cleaner on Tuesday. Yesterday when I drove it three different times the CEL did not come on. The day was a little cooler around 22C and maybe that had something to do with it.

Today it was raining 14C and the light has not come on. Maybe the injector cleaner has fixed something?

Here are the screen shots from the scanner.

 

Howdy!

I recently had the same codes pop up simultaneously, but I don't recall whether or not the fuel trims were equal. Ended up being a vacuum leak in the PCV elbow just off the PVC valve cover (on intake plenum). Here's a link to a thread I posted about it, hope it helps.

https://blazerforum.com/forum/2nd-ge...olution-90048/