2013 Fiesta SE Accelerator Pedal Issues

[Vargrklaw]

Hi, all, newbie here. Just picked up a 2013 Fiesta SE 1.6L that I was aware had some issues, but didn't know to what extent. Already got a couple sorted with lights and such, but this gas pedal is driving me nuts. Using ForScan, the PCM has codes P2126 & 2127, and the IPC has B1029:11 as well as the throttle is slow to open, but immediately snaps shut when you let off the pedal. I know those codes can be related to TSB 13-11-15, so I started looking into that and turns out some of the work had already been done, just had to swap the wire locations on the pedal and cluster plugs. Still the same codes, so after digging in more, I discovered a non-factory wire running from the pedal plug, taped along the harness and then out the firewall to patch into the middle ECU plug in place of the Yellow/Red wire on both ends.

I was told the motor was replaced with a good used one about 50k miles ago, but wasn't told about that wire. I removed that wire, stripped and twisted the Yellow/Red back together on each end, but still the same issues. At this point, I'm not sure where else to look, so I'm asking for help. I'm beginning to suspect maybe a faulty pedal, but my gut says no because it's still working, just the throttle plate is slow to open. I imagine that's some form of limp mode?

 

[Vargrklaw]

I feel I should add; The engine runs REALLY nice, even without being able to quickly rev. I drove the car from Tulsa, Oklahoma back home to Owatonna, MN, which was just over 600 miles. Never had any real issues other than burning some oil at first, but that cleared up after an oil change because I think it was about 1 to 1.5 quarts overfilled. Within thirty minutes of freeway driving at 70+ MPH, no smoke at all and no weird noises to speak of. Also just couldn't use cruise control, so my foot was real tired by the time I got home. Engine fires right up within two seconds of turning the key, idles very steady and smooth. I have no reason to believe the engine itself has any problems.

 

[Vargrklaw]

Got a little more, hopefully relevant, information. Using ForScan and watching the oscilloscope with APP_D & APP_E %'s active, I see APP_D maxes out between 65-70%, but APP_E only gets to about 3.6%. I was reading something that I wish I could find again that said APP_E should be approximately half the value of D. Is this any indication of a pedal issue? I pulled the pedal out to inspect it and immediately saw it's an aftermarket Hella unit, which I found on RockAuto for less than $50 compared to $200+ for the OEM Motorcraft unit.