Fuel sending unit problems
 

2001 ram 1 ton dually, noticed one day my guage was at 1/8 tank when i was stopped out of fuel. Got it diagnosed then noticed it bounced around when full. Bought sender from a dealership ebay acct. I removed the old and tested its resistors and they were good but the float wasnt attached to the arm on the resisitor. Decided it was better to just install new since the hard part was halfway done. Now my new sender stayed at full all the way through a 150 mile trip. I could tell something wasnt right, dropped tank and checked connections and it had 136 ohms so i knew that was around half and reconnected and the guage was between half and 3/4. Now it moved up to 3/4 and stayed there. Want ideas as to why it would do that and what a cure would be.
Thanks

its not hitting the tank on the inside anywhere is it..

I don't think it would be. It worked for a bit and now its a bit above half and staying there with about 150 miles since it hit that point.

2 reasons for a gauge to stay in one spot. Sender failed, or the absolute perfect resistance in the signal wire or ground. What are your goals for the truck? Stock, or a performance truck? Do you have an intank pump?

Just a stock truck for good mileage driving and it seems to have adequate power when towing heavily. Ive done a bit of reasearch and need to. Check the ground in the engine compartment. That would make sense since the truck sat for five years before buying a new vp. And no I went with a Fass due to a lifetime warranty.

Checking everything out now, the connector under floorpan is good i checked ground at the tank qnd good but it didnt even occur to me how hitting the tank could affect it until i came back to the thread so i am checking it right now

And hitting the wall was the problem i had turned it to be easier on the hoses going to the ip when i didnt pay attention to where the float was.