Not long after I first got my RRS 4.2 S/C, just over a year ago, I started getting an occasional engine warning light illuminated, along with the code P2135 (Throttle/Pedal Position Sensor/Switch A / B Voltage Correlation). The car seemed to drive perfectly, but as the months progressed, the light started coming on more and more: I'd clear the codes and it'd come back the next day or the day after, for example.
I bought a brand new throttle body, thinking it would resolve it, but it made no difference. I then removed the trim under the driver's side kick panel and unplugged and replugged the throttle pedal connector, and if anything it seems to have made it worse: if I clear the code now, it comes back within only an hour or so. This could of course just be coincidence though.
The weirdest thing however is this: when I drive to the US from Mexico, where I live, the light still comes on, but nowhere near as often. I've been thinking about the reasons behind this and I've come up with the following three:
1) The gas I fill up with in the US is better than gas in Mexico. This seems unlikely though, as I fill up with 92 octane in both countries, and the fault doesn't seem to be a fuel related code.
2) When I fill up with gas in the US, I fill it up myself, whereas in Mexico an attendant does it. Perhaps I screw the gas cap back on better than they do, although this also seems unlikely as it happens virtually every time in Mexico, and the fault code doesn't seem to be related to the fuel / EVAP system.
3) When I drive to the US, I spend long periods on cruise control, where I'm not touching the accelerator pedal. Therefore, maybe the fault is in the pedal itself, and as I'm not pressing it anywhere near as much when I drive to the US, the fault appears far less. I feel like this is the most likely, but a lot of people have told me that when a P2135 code appears on these trucks, it's nothing to do with the accelerator pedal itself and must be within the throttle body. However, as I've changed the throttle body for a genuine part, this seems unlikely.
I get good gas mileage considering the type of vehicle, and the truck seems totally unaffected by the issue, other than the EML illuminating. I'd just like to get it sorted as when I sell the car in a few years, nobody will believe me when I say the EML genuinely doesn't affect it, therefore I'll get a lot less money for it.
So, any ideas / opinions on my theories?