90 245 erratic fuel gauge reading

[brickhead]

Good evening all.

My ex girlfriend has been having fuel gauge issue on her '90 245. She called and told me that recently she had need to fill up and her car but she could only 3 gallons, set the odometer and at 95 miles, she was out of gas.
Luckily there was a station where she rolled into and filled up the tank 15.35 gallons she said. She added that her stall once in the past but thats it.

She took her car into her mechanic and he said that the filler is rusty. Well it is a 25 year old ride. If the filler neck is really bad, wouldnt the check engine light come on? Evaporative leak fault?

I think she has a faulty in tank fuel pump. Unfortunately im a couple hours away so i cant check the fuel pump relay or the car out to if its ever been changed.


Any thoughts?

Thanks in advance.