Don Vito

Hi all,
I could use a bit of help diagnosing my engine misfiring.
My engine is a 04 5.3 with Texas Speed 224/224 cam and 4" cold air intake with flat blade style mass air sensor and a drive by cable LS6 intake. This was dyno tuned and ran great now I have a very rough idle while in gear and a slight misfire when running at a constant speed the latter is not always present.
I have changed both coil harnesses, inspected the plugs they smelled like gas but looked clean (oh and the car is definitely running rich) and last I cleaned the Mas air sensor.
Car is definitely running rich and my fuel economy is down.
The only diagnosing tool I have is a code reader that will show me some live data. Any thoughts would be appreciated.

Thanks George

Don Vito

Found the issue it was a poor crimp connection at 12vdc supply at back of fuse pannel.
Caused a high resistance issue that almost started a meltdown.

joecar

So now the misfire is fixed...?

Don Vito

Yes Sir runs smoothly now. I haven't looked at my wiring diagram for my fuse block yet to see exactly what was affected but I'm assuming a loss of current affected the power output of the coils