Before everyone starts with the Techron Plus additive, please read.

Gas gauge WAS working fine. My car has the old RSI dual walbro 255 system installed, but it had an interal leak inside the gas tank because of some lines that were not capable of holding up. I took it to a shop to have the issue diagnosed and fixed.

Once he found and fixed the initial issue, the shop owner noticed a gas gauge issue come up. It wont read over 7/8th of a tank, and then the gauge will go all the way to empty, and then after driving through half the tank, it will randomly come back and start working again. He pulled the unit again to attempt to fix the issue and even ended up replacing the sending unit, but the problem still remains. Could the problem be the passenger side tank? maybe a wire was pulled/broken on the install?

I have already disconnected and cleaned the two connectors that are down by the drivers side tank with electrical connector cleaner and added some Di Electric grease but that didnt help. I did One tank of Techron that I purchased from Walmart, but can't remember if it was Techron plus.

I'm getting ready to drive the car home on a 1300 mile trip and am hoping to get this issue fixed within the next week. Please help guys, this crap is driving me crazy...

 

I have gone through three full tanks of gas. Last tank went down to E.

 

There is a sending unit in each tank. The good news is it sounds like the jet pump is working so you could drive utilizing both tanks. You would need to keep track of your mileage to ensure you don't run out of fuel.

Based on your description, you have a faulty sending unit. Have you pulled your codes?

Mine did the same thing. If you drive for about 100 miles continuously, the gage will drop to zero because the computer isn't seeing a change in level from the fuel sender. I would stop and the car would only take a half tank of fuel. Other times, the gage seemed to work normally and then there was my favorite. I would have a 1/4 tank (actual and indicated) and drive for awhile then the gage would "gain" fuel.

You need to start tracking your miles driven until you fix the problem. Otherwise, your gage will catch you off guard and your tanks will be empty.

 

I will pull the codes and post shortly.

 

10pcm p1431 h c
40 bcm b0432 h
ao-ldcmu 1064 h
a1-rdcm 1064 h
bo-rfa 1064 h

 

DTC P1431 Fuel Level Sensor 2 Performance. You will likely have to replace the sender.

 

I agree that the sender needs to be replaced. That is the same code (p1431) mine was throwing.

I replaced the pumps and senders since my car had 199K miles on them. I've driven approximately 4K miles since the first week of July without another issue.

 

Is sensor 2 the passenger side?

 

The shop that did the work wants me to bring the car back in, but there is a little wait before they can get to it. The mechanic suspects that the issue is the wiring of the sending unit inside the tank. Tomorrow I will run the tank dry and pull the unit to check it with a volt meter. I will post what I find.