I thought my float was maybe turning vertical and getting struck that way but I'm pretty sure in my case it's electrical. I cleaned the contact wiper once when it was reading like 35L high and it worked right to zero for a good while.

Then one day I noticed my DTE got to about 37 miles and just hovered there. Pulled up the test six and it showed less than 1L on the right side meaning the left is bone dry.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)