Whats up folks, I am new to this forum, been on silveradosierra.com and merged my way over here because you folks were a good reccommendation on info that I may need. Lemme tell you about my setup, I have a 2011 Sierra 4x4 with the 5.3 with 8000 miles and I had a custom intercooled manifold built for it with a eaton blower on top, got some Dodge SRT4 stage two 55lbs injectors for it that pump out more than enough fuel for it and starts right up and runs, my issue is that I took it to the tuner and he hooked it up to a tech 2 and says its misfiring bad on cyl 4 and some on cyl 3, I had the injectors cleaned and pressure tested and they are good, did a compression test and it hit 170, new NGK plugs, tested the coil wire and its good, im running 91 octane and there is no cylinder leaking from the manifold to the cylinder head and I have no clue whats next.

 

Is it misfiring all the time or only under a load? Do you have a wideband? If you can, post up some pictures of your setup so we have a better idea of what you are working with.


Welcome to the site by the way.

 

Misfires all the time, no port to put in wide and in. I will post some pics in a bit

 

Ok, so 3 months later I upgraded the injectors and still same problem. Only misfire on idle on cyl number 4 but not under load, (had a tech 2 hooked up while driving) wideband it way in the 10's when boosting and runs 14.4 when driving normal. The tune isnt 100% bc he does not want to tune it until the idle misfire is gone