I have read several posts about cel 25 and 26 (25 means lean, 26 means rich) but non of the remedies have helped yet. Here’s my story

I recently put a stage two rebuild from 22re performance in my truck which has the following mod over stock. (pulled from their website)

. Ferrea 45.5mm (1mm oversize) stainless steel intake valves
. Ferrea 37.5mm (1mm oversize) stainless steel exhaust valves
. Port, polish and blend work to intake and exhaust pockets
. 280 or 270 / 440 OEM reground performance cam (for EFI) depending on the year of your truck (each grind/lobe seperation configuration depends on the year of your truck)
Performance 75lb. valve springs made just for us!

I have also done an air intake/battery swap with hidden snorkel. The snorkel is in between the fender and the engine bay.

The motor has been running great for 400 miles except for an exhaust leak that was due to a warped exhaust manifold. Last week I installed a LC engineering exhaust with a flowmaster 40 (no cat). Two days after this the truck started throwing cel 25&26.

I have taken the following trouble shooting steps
➢ Replaced 02 sensor with a bosch (could not find a denso)
➢ Ran propane torch (not lit) all around intake and vacuum lines
➢ Checked timing it was 5degrees jumped and 12 not jumped
➢ All spark plugs are firing and I will attach pictures of plug condition
➢ Truck also has new TPS tested and in spec

ALSO Do you guys think I should try advancing my timing with these mods? If so by how much?

Thank you greatly for all your help

 

Here are some spark plug pics if this helps any.

 

I hope you figure this out, I am in the same situation.

 

have you tried changing the air fuel mixture at all?