Fuel level sensor

Hi all  I'm working on a 08 hyundai santa fe 3.3L. I was checking pcm grounds because I have a very intermittent loss of sensor signal on my scan tool. I've seen it on tps, app, o2s, fuel tank pressure voltage. It caused a stall while driving but hasn't stalled since even though i see the dropout on my scan tool. No codes. My question is when I checked the ground (car idling) for the fuel level sensor/ fuel sending unit it was around .3mv. I then checked the signal wire an it was 6.1volts. I shut the car off left the key on an the voltage on the ground wire slowly crept up to about 2.5volts. If I start the car it slowly goes down to .3mv. I'm guessing this is right since I don't have any codes and my fuel gauge seems to work but this doesn't make sense to me. Has anyone seen this before?

That does sound like a poor ground on the fuel level sensor circuit. I have never seen one behave that way. Did the fuel level gauge or data PID change with this elevated ground voltage?

I didn't think to check the pid at the time but the gauge didn't seem to have fluctuated at all and the pid an gauge when i check them seem to be in agreement. I can't post pics at the moment but all the grounds on the c130A connector seemed to have spikes or more erraticness compared to the grounds on the c130b. I did check where the computer grounds to the chassis didnt see any voltage drop.  I'll try to post some pics later. 

some scope pics of grounds and what appear to me to be faults.  

Scantool dropouts