Fuel guage/ range reading.

I have an 04 Silverado LS 1500 2wd ext cab with the regular non flex fuel engine. This truck has been excellent with no problems, until yesterday that is! on my way to work, about 14 miles, my gauge went from 1/4 tank to light on when I arrived. When I started it to leave from work I had went back up to just under 1/4, but then it started acting like a tachometer, and the range reading on the DIC went from 90 miles down to 36 and just fluctuated up and down from there.

Now when I start my truck, the fuel guage points to somewhere no where near where it was when I parked.

I spoke with my High School Auto teacher (who works at a Chev Dealership) and he said that ocassionaly there is silicone contaimination in gasoline, and that it coats the sender and gives a false reading. He said to try using a bottle of Techron additive to clean out the silicone. Has anyone heard of/ tried this?

He also said if that does not work, to replace the unit, I have read on here that the sender is actually seperate from the pump, is this true? or do I have to replace the entire unit?

Any advice is appreciated, C.J.

silicone contamination, huh.... that's a new - and good one.
donno about techron, you supposed to use chevron anyway, but nothing beats seafoam as cleaner.
chevy trucks are notorious about having bad ground wire on pump and sending unit, oxydizes very fast and then it all goes coo-koo. if you can get to it without dropping fuel tank - good for you.
also, word of the mouth is - chevy has recall on instrument clusters for some VINs. inquire with dealership.