Gas gauge reads 1/4 tank on full tank of gas

[tucsonjwt]

If you replaced your sending units with aftermarket units (I used Spectra), then you will get a bouncing fuel gauge on bumps, turns, stops - at least that is my experience. But I think you are in a whole different ballpark - electronic fuel injection, different sending unit, even different type of gauge required - I would suspect. Unless, of course, if you topped it off with a carbureted intake, etc. How much of the modern 5.3 setup did you use? I am thinking that engine is not set up for old analog gauges, with regard to electronics controlling it. I think the hot rod conversion guys probably figured this one out already - might try them.