johndeere01

I had a new sensor installed because my truck would not stop throwing the code so they said the sensor was bad this being after they progrmmed it out and it still throws the code it dosnt do it as much an only seems to do it right after start up the volt gauge will drop to nothin check gauge light comes on and the MIL light then it will come back up an drop back down to nothin an then fianlly come up slower than normal probly about 5 miles down the road to the right side , My question is what can be done to stop this?
thanks dennis