Where is the DI Ecu located?
 

Can someone post a picture of where this is located?

On passenger side of engine near valve cover. Large black box with harness.

On the passenger side above the injectors

https://i.imgur.com/Ues934P.jpg

So this one, right? I read that the bottom bolt can cause grounding issues and I'm going to try and see if that will rule out my issues. It looks really tight...how can I even screw the bolt down there? Would I need to jack my engine up? :x

That's it. If you can see the 3rd bottom bolt going into the block and it's tight, your ECU is grounded. What are your issues?

Got a lean code (P0171). Fuel trims are actually pretty high so it could very well actually be lean. Was just trying to rule out a possibility.

Thanks!

Alternativly you can run a ground wire to chassis ground from the top bolt

I got this too. Turns out the aftermarket in-tank fuel pump was not seated properly, dropping feed pressure to 38 psi. The DT flex fuel kit I have saw an out of limit low pressure and zeroed out the ethanol content signal to the ECU, making it think I had 100% gasoline instead of the e85 I actually had. It then was running leaner than it should have been, my STFTs pegged at 30%.