2008 ram, 6.7, egr delete, smatry 6.7 me, 142,000 miles. I got a code recently p0471. Truck defueled, limp mode I assume. Tried clearing with smarty, it worked for about 3 miles, defueled again, could only get home at 12mph. cleaned tube, orifice, and sensor 4928594, no improvement. used smarty to clear and switch to no3 level, no change. waiting on new senor. Anything else I'm missing? Will I need to get reflashed after I change the sensor?