I have an 87 IROC and the fuel gauge recently went wonky prior to fueling up and then after fueling is now pegged beyond full. Also, the car has been stumbling a bit. Don't know if the two have anything to do with each other...any help would be greatly appreciated.

Thanks
Melissa

I believe that the fuel gauge will peg when the ground is removed from the sending unit. There should be a ground wire coming from the top of the unit and going to the car body.
The stumbling is likely unrelated.

I disagree...

The fuel pump and fuel sender share a ground, so if the gauge is ***** and the car is stumbling the ground is the first thing to check. The ground wire comes through the back of the cabin, behind the rear seats and under the trunk portion of the carpet. I don't know where the ground terminates...you will just have to follow it or you could check the continuity to ground of the black wire associated with the fuel pump/fuel sender connection.

I hope this helps.

Thanks for your help. I will check the ground and let y'all know the outcome.

my 86 has this ground under the left rear seat ,near where the wires for the fuel tank go thru the body

Thanks. I'm going to attempt this fix over the weekend. Thanks for the tip.