Update. Got the iac issue sorted out. The connector pins were stretched out. And yes the air tube was leaking. I reattached and now it's sealed.
I finally got a factory air box too. So she idles just fine with no hunting or surging. On start up she runs around 1200 rpm and over a couple minutes
comes down to around 950. I'll need to set minimum idle speed but it's fine running high while I'm testing. It goes closed loop about 3 minutes after start up.
The older ECUs take way longer to go closed loop. My 88' Bronco wouldn't until it reached 160 degrees. I don't know about the A9L or A9P ECT.
Getting in closed loop faster is better for emissions. Upon going closed loop it starts adjusting STFT based on o2 switching. Bank 1 is now switching normally.
Bank 2 isn't. Bank 2 STFT goes rich to try to make the o2 sensor respond. after a few minutes it gives up and starts adjusting STFT based the bank 1 o2 sensor.
Thus acting as a single o2 sensor system. The bank 2 o2 sensor harness side connector is broken and not fitting good. This is causing a poor signal.
Otherwise everything is working as it should. Since This is an automatic ECU for a 4R70W, it's wanting to see the transmission range in park. Without the MLPS connected the ECU defaults to overdrive. Sure it starts and runs like this but drive and park/neutral have different idle strategies.
This was the only ECU I could get at the PnP. Of all the mustangs the only 5.0 was an automatic. But I needed something to get the car running and foe $35 it would do.
I put a potentiometer in between the transmission range input and reference voltage. I'm able to run through the ranges and park is about 4.3 volts.
You can hear the sound of the engine change when it shows park. The timing drops a little and it's almost a 50 rpm drop.
So it drives, it's got some issues though. I put it in reverse and I let it creep backwards, then drive and pulled out of the shop. Well t brakes don't seem to grab.
I did a doughnut and drove back into the shop. I had to turn the ignition off because I can't get it out of drive. The shifter cable is messed up.
Rear brakes don't grab. The front brakes are fine. I replaced the hoses, pads and master cylinder. I bleed the whole system and I had good pressure at the rear so I left the rear brakes alone. Well, I had to beat the drums off with a sledge hammer. Their all rusted up. Actually the shoes are good. They don't look like they have many miles on them. So I'm going to replace all hardware, cylinders and drums.
The shift cable tube that that guides the cable is broken so it pulls back fine but to go forward the cable bunches up.
The best price I could find for the cable is $89.99 on rockauto. People want more for a used one on ebay.
In the pic you can see the metal tube is broken. I have attempted to jb weld it but no good.