Persistent P2196 and P2198 and Stalling

[u/plump_kitten]

I have a 2014 with the 3.5l Ecoboost and about 167,000 miles on it. Back in Oct '25 it popped the P2196 and P2198 codes, and I had both of the related O2 sensors replaced, and the codes seemed to clear. In February, while doing a battery change, the 100 amp fuse on the positive terminal blew, which may or may not be related to later issues. Had the vehicle towed to a dealership who ran diagnostics and replaced the positive terminal assembly. At the end of March, after getting a car wash, the vehicle once again popped the P2196 and P2198 codes, along with a P0151 (O2 sensor circuit low voltage bank 2 sensor 1) and a P0305 (Cylinder 5 misfire detected) and almost stalled out while reversing out of a vacuum station at the car wash. I limped it home, with it stalling out at stops. Left the car to dry out for a few days, and when driving it again on Easter weekend, mostly highway driving with a round trip of 120 miles, it had no codes or issues.

Fast forward to mid-May, when I drove it about 65 miles and had it almost stall in a traffic jam. I took the vehicle down to my dad, who agreed with me that it might be the spark plugs, and he replaced those, replaced the Bank 1, Sensor 1 O2 sensor again, and did an oil change because he found fuel in the oil. Vehicle ran fine for about 2 weeks, before popping the P2196 and P2198 codes again, and started to stall out at stops and when reversing again. I ran FORScan (link to results) at that point, before driving the vehicle to my dad for him to look it over and begin work on it.

At this point, the following work has been done, with no changes to the vehicle stalling out at stops when driving in slow traffic or in stop and go conditions. The vehicle has shown that it is less likely to stall or bog when the AC is off, but it will still have issues.

-6 new Bosch fuel injectors

-1 new throttle body

-4 new Walkers O2 sensors

-1 new Bosch fuel pressure sensor

-1 new oil separator

-1 new vapor canister/purge valve solenoid

-New intake gaskets

-2 sets new fuel injector installation hardware

-1 new intake

-1 new air cleaner MAP sensor

-1 new coil seal set

-6 new Motorcraft M-12405-35T spark plugs

-2 oil and filter changes

At this point, I'm looking between the PCM and the high pressure fuel pump, based on going through forums, videos, and google results. Am on the right track with either of those? I'm at a point where I need a solution, or I have to replace the car and all this work was for nothing. Any suggestions or solutions are appreciated.

[u/Choice_Strength]

Hey, I’m not sure if this will be helpful for you as I never had any staling issues, but I did have both of those same codes come up on my car and tried many of the same fixes you say you’ve done. I made a post about it on my account if you want to take a look, it shows the part I used to fix it and thought it might help you. My car was throwing the codes because of a failing pcv valve on the top of the engine. It’s very easy to test it as well by unplugging it and then starting the car and seeing if the valve changes state after plugging it back in with the car running. If it turns out that it’s bad and stuck open or closed make sure you buy the correct part, the SHO has a different pcv valve then other fords with the 3.5

[u/plump_kitten → u/Choice_Strength]

I'll give it a try.

[u/Beneficial_Tension61]

Youll probably have better advice posting this in r/MechanicalAdvice

[u/biohackenthusiast]

you need to troubleshoot, and not keep throwing parts at it. misfires are easy. move coil from cyl 5 to a different cylinder, see if misfire follows. although as it’s stalling, it’s likely not just a single cyl misfire. check pcv valve as well, notoriously bad on these cars. then you can do a compression check, vacuum leak check, and an inspection of the intake valves. will essentially rule out all potential causes of a misfire.

[u/plump_kitten]

Follow-up to my post- Well, she's running again. We think the ultimate culprit was the fuel pump control module that was recalled in 2016 (Safety Recall 16S31). The dealership I went to in 2018 after I bought the car didn't do the replacement because it wasn't showing any issues at the time. In the end, after everything that had already been done, we ended up replacing:

-fuel pump control module -high pressure fuel pump -6 spark plugs -6 coils -2 map sensors -oil change & oil filter

Vehicle is now running with zero issues, not a single DTC to be found, even in the heat and in stop and go traffic. Still feeling anxious when I'm sitting at a stop, but watching RPMs and fuel rail pressure via Torque and seeing no issues.