I did a Silverado swap, 03 4.8 to a 04 5.3. I used the 4.8 injectors on it and now it runs lean. The pcm was tuned for a 5.3 with 5.3 injectors. I thought they were all the same? unless it was a 99 or flex fuel. Anyone have some 5.3 injectors, preferably 04.

 

na flex fuel use larger injectors for the e-85.
something was not tuned right.

 

what you thought was correct, they are the same. are you running an aftermarket cam? do you have access to tuning/ logging equipment?

 

nothing aftermarket,just a plain ol swap. No tuning equip, but I do have a tech 2.
It runs +25 fuel trim. new intake gaskets, new 5.3 02 sensors. The 4.8 ones set a heater performance code. Anymore help is appreciated.