2000 S80 intermittent no start and other issues
 

I have a no start issue that has gotten worse. I wrapped the power lead to the starter, cleaned the throttle module, replaced the crank sensor and ran a couple new grounds, no difference. Today it was starting then stalling or not starting at all and when it finally did start the idle was going up and down on its own and it was sputtering at an idle. And if I held a high idle it would still sputter. The brake light, ABS light, STC light all came on as well as 'Brake Failure Stop Immediately' which I thought had been fixed with the new ABS module but I guess not. Only the fuel gauge worked as well at the time, the speedo, tach and coolant temp were all zeroed most of the time but the tach would hold a steady RPM reading when cranking. Also the shift light with either be stuck in park or not on at all. When running the oil pressure light was on. I hooked up the scan tool and watched data and the O2 sensors were all moving and it was reading RPMS but the two things I noticed were that the 'Absolute Throttle Percentage' reading never left 9.4 even when revved and the ignition timing was almost always negative. I also pulled codes P1833 and P1631. I sent the ECU out for testing and they found nothing wrong. Could it possibly be the throttle control module. Should I look into a new throttle module or possibly the updated fuel curves, it was never recalled on either. Any help would be awesome I am kind of at a stand still at this point.

Update....
 

For some reason I thought to myself to disconnect the battery for a minute and see what happens and guess what, the car started and ran great and all lights were gone. So does anyone have any idea what is going on here, I found one other person with the same problem as mine with no update as to if he fixed it or not. Very puzzling!!!!