The dominant bank is bank 1 or bank 0 as it's written in my tune (cylinder 1,2,&3). If there is that much fluctuation between banks the ecu will disregard bank 2 o2 sensor and likely throw some codes. I think there is another issue you are having. I would look at vac leak, o2 sensor, or a bad injector. The stock mustang upper intake is very similar to the ws as each bank has it's own plenum, the mustang intake is just top entrance where the ws is fed from the front.Just look at the STFTs at any one point in the data log when the throttle counts are less than about 50%. One bank may be showing 5-10% higher than the other or conversely 5-10% lower than the other. Think about how the PCM will decide which bank to trust or trim A/F numbers. For example, bank 1 may be 1.05 Lambda and Bank 2 could easily be 0.95%. Which way would you adjust the MAF to change the A/F ratio when the wideband is showing 13.2:1?? And, by how much??
Very nice job
Disclaimer: This is how I did my own conversion. There are many things that need to be fabricated so if you don't have the skills or the balls don't try this. Also there where a few things that I wouldn't consider the smartest thing to do to a car but were needed.
Full socket set
Drill + bits
Hole Stepper Bit
Vice or a clamp and table
Wire crimping/cutting tools
die grinder or other cut off tool
Cobra R hood
Manifold w/ isolator bolts
3/8" phenolic spacer
Gasket material (a must)
New upper gaskets (one for a stock upper and all for the windstar manifold)
EGR delete (a must)
Intake tubing (I used a 90 and a 45)
Intake hoses (too many to name)
2" wide aluminum plate
1" wide aluminum plate
2 Barbed 3/8" fittings (for remote IAC)
A tap for those fittings (1/4 NPT) maybe different depending on what you pick up
2' wire 3 different colors (for lengthening the TPS)
Various wire connectors
OK start by removing your EGR system. I had to cut the pipe close to the header with a die grinder so I could just put a socket over the end.
Remove the solenoids, pressure sensor, and valve from head. I pulled the wires back and zip tied them to the fuel rail. Then cap off the port on the head.
Next I deleted the PCV system by switching the pcv valve and cap from one side to the other. Them putting a vacuum cap on the driver side and a breather on the PCV valve on the passenger side.
After that was removing the stock upper manifold. This is pretty simple: first remove the air filter and tubing, then the throttle cables, next the vacuum lines, also the connectors for the TPS and IAC, on the coil pack just simply unbolt it, and finally the 8 bolts that hold it down.
NOTE: there are two fasteners on the back holding the wiring harness to the upper plenum.
So now your upper is off and the engine looks sad, I took this opportunity to clean the lower the best I could.
Here comes the fun (and stupid part). Even with a 3/8" spacer I still had big clearance issues with the bypass vent and fuel pressure sensor. I used a 1" ID conduit pipe to bend the vent towards the driver side headlight (pull very slowly and only a little at a time), Then used a flat wide bar and a hammer and hit the fuel rail on the fuel pressure flange twice to move it (this made me very worried). Next you have to remove the dowels for the lower and replace them with ones long enough to go through the 3/8" space and the new upper (mine were too long so I cut them with the die grinder until the fit)
After you get those clearance issues fixed It's pretty simple. Install the spacer with a new gasket under it. Them replace the gaskets on the Windstar manifold and Bolt it on (be careful as this manifold only needs 15lbs of torque to hold it down). I then Fabbed up some brackets to hold the Throttle cables, coil pack, and to remote mount the IAC. The IAC bracket is the only one I will go into detail as you can see the others and figure them out.
On the IAC I made a flange out of 2" aluminum plate from Lowes. Simply use a gasket and trace the pattern on the aluminum. Cut out the (outer) shape using a cut off wheel, hacksaw, whatever you have to cut straight with. then use the inside guidelines to find two places to drill for the barbed fittings. Next tap them and use teflon paste on the fittings.
With the TPS you have to lengthen the wires about a foot. Just some simple 14ga wire and connectors and that was done. Since I remote mounted the IAC I didn't have to lengthen those. I just mounted It with some zipties and was done. There is a vacuum port right behind the original IAC mount so thats perfect for you remote mount manifold side.
My biggest headache was the intake tubing! I bought a 3" 90 degree and wanted to run it to the stock hole in the fender support. That was impossible with what I had. I figured to run it under the frame rail and inside the splash guard.
I went and bought a 3" 45 degree and 2' of 3" coolant hose for O'reilly's and went to work. I made a vacuum port on the tract halfway down for the remote mount IAC. Then made a hole big enough for the MAF in the splash guard. (you must buy a new coolant reservoir)
Almost done! Just get the rest of the vacuum lines on, mount the coil (including the clip), and mount/fab some throttle brackets.
That was pretty much it!
DYNO COMING SOON!!!
Manifold w/ isolators 50
throttle body spacer (optional) 35
Cobra R hood (optional) 235
egr delete 30
Thats a high estimate if you have the materials laying around and dont want the hood its less than a hundred. I spent much more just because I bought a tuner, phenolic spacer, 70mm throttle body, and other things at the same time.