Best Answer acdii , 22 January 2014 - 02:53 PM
Source of discrepancy found! I finally got around to documenting the trip screen prior to shut down and after startup.
When I got to work this morning, I took a picture of Trip 2 moments before shutting the car off so I would have a record of run time, and fuel used. I had forgotten to take the picture, so I started the car without the brake being pressed, so reason for CEL.
When I went out to lunch, I had remote started the car, called my wife to let her know I was on my way to get her, then noticed the snow on the car and proceeded to clear the snow. By the time I got in the car ready to start it(did not check to see if it would start without pressing the brake(sorry different thread)), it had been running for at least 5 minutes or more. I had the camera ready and as soon as I pressed the button, and the screens cleared, took another picture.
So it appears that remote start run time is not accounted for, nor is fuel used during that time. This would explain the gallon and a half difference between what the trip said was used and what was actually put in, and also explains why the fuel gauge and DTE doesn't correlate with reported MPG. Going back to the PDF posted in another thread on how the Fuel gauge is used, this makes perfect sense now. It doesn't explain why an apparently empty tank only takes 11 gallons, which I still believe is just a calibration issue between the fuel sender and the PCM.Go to the full post