The banks are not independent. This observation is irrelevant.
I think your problem is electrical. Bad ground, bad PCM, bad wiring. I'd start looking at chassis grounds for corrosion, indications of poor grounding.
STFT's should always fluctuate, and target 0. seeing a slight - and slight + number back and forth is exactly what it should do.
I don't think you're going to notice a difference at the tail-pipes if one cat is plugged. I think the exhaust system balances things out by the time the gasses & moisture get to the end.
Cats don't effect fuel trims, Fuel trim effect cats. If you are running rich or lean is what will cause a Cat to fail. If you were having a leak post MAF (vacuum leak), or were having fueling issues, your fuel trims would not be as close to 0 as they are.
That make sense, I assumed that the exhaust could be an indicator of health but there are a lot of checks in these cars. They said they didn't replace the passenger side because it wasn't throwing a code and that's why I've been hesitant to even take it with an intermittent issue.
I just installed a new OEM throttle body and already notice a slight difference. The squeal is more of a gentle high chorus vs glass breaking screech. Shifts have already adjusted but there is still some breakup in the tone of the exhaust. I'll checkout the connections at the top end of the motor and see if there's anything that stands out.
LTFT's should stay consistent, and be as close to 0 as possible. STFT's should fluctuate back and forth, but also as close to 0 as possible.
Doubt it, just not taken care of previously. I change my oils at half the regular intervals just to take care of her.
One thing I've been trying to figure out is it sounds like air trapped in the fuel rail. I know that's unlikely but it makes noise near or in the fuel line after the hp fuel pump. This is new and just started happening last week immediately after the last bucking. That noise has remained constant. It echoes through the ccv line and putting my ear on the fuel rail I can feel it in the area between the 1st and 2nd injector on passenger side.
Disconnect the fuel line and see if the Oring is pinched or rolled.
I got earballs for that my good sir. That sounds like a good call for this issue. I will report back after checking.
You'd be surprised how noises and vibrations can echo through stuff, and mislead a diagnosis. There like 10 bucks at Harbor Freight
Well ive made some very surprising discoveries... after pulling out the drivers side pump and installing back in I now get ~16 gallon fillup. I watch pretty much all the data you can in the car all the time and all the time since getting the car it's been 8 gallons at 1/4 full. This morning I got 10 and it was a good bit under the 1/4 line. The throttle body cleaned up everything and then some (lurching when putting vehicle in drive) so far. I believe I've put enough miles on her to learn my behavior again so I'm assuming this is the new learned behavior from throttle body replacement. The noise on the passenger side is still there. Turns out however that line seals is integrated in the line so it's 107 at ford. They're on strike or else I would've thrown it on but the more I think about it I think it's either the first or second upper injector clogged up with stuff. I've ran a fuel treatment for upper end cleaning and lubricity with no change. The throttle body has made the biggest improvement so far but I can't sleep knowing that noise is still there. I might just throw a set of upper injectors on the car since it's getting close to 50k miles anyway.
You obviously are doing a lot of testing and investigation already. You also shared a lot of good information on the forum, so understandably the amount of data is overwhelming to some (like me). But good info nonetheless.
I have put about 350 miles on the car since getting the throttle body and wow I thought I had a gt before this thing is brand new! Everything's cleaned up except that rail noise but even the cold starts are the same everytime now. Sometimes it'd hot start weird too but those are gone. I did have a weird time getting the drivers side fuel pump out. The line that runs to the other pump was twisted and I had to finesse it to get the pump out. Installing was 100x easier than install from that issue alone. I'm assuming inside the tank wasn't happy from an accident earlier in the year. Just got the car back about 2 weeks ago so it could've been that or another weird issue. I'm going to keep monitoring everything and hopefully I can relax soon over this stuff
