O2 sensor questions with tunning

[Burns331]

I have a Grpyhon on my truck that Bill custom wrote me a tune for so that i can run my 5.4l engine on my 4.6l coil pack/ecm setup.


Anyways, i know for a fact that his custom tuning blocks the rear O2 sensors, because when i put my long tubes on and got rid of my cats, i never got a code.


But here in the past year or so my truck has developed a rough hesitation from 1100-1450 rpm. It barley wants to pull through it, but once its to 1500, it runs perfectly. And it runs great everywhere else in the power band.

I also have no relivant codes to this issue.

Does the custom tuning also block codes for the front O2 sensors? Im very close to changeing them out, they do have 225k miles on them.

What kind of symptoms on these ECM's would you get? I know bad o2 sensors can make different symptoms based on how smart the ECM.

Thanks

[88Racing]

The front O2's are still needed so they are not blocked....

Try to do some cleaning of the tb/iat and maf, change your fuel filter also.....

[Burns331]

I know that the engine is still reading them, i just didnt know if it would still show a code or not.

I will take a look at the TB/IAT.

[88Racing]

Originally Posted by Burns331

I know that the engine is still reading them, i just didnt know if it would still show a code or not.

I will take a look at the TB/IAT.

The front O2's will still throw a code....

But

As the miles increase on these sensors the reaction time becomes slower....

[Burns331]

So with 225k on my original sensors, They could be causing my hesitation from 1100-1400 rpm. They are working, but the engine is leaning out possible?

[88Racing]

With 225k miles changing them might be in your best interest ......