1976 Fiat 1800cc Sport Coupe- stalling problem

[JoeW]

In the fall of 2024 I first noticed that for the first time since I’ve owned the car for almost 30 years, when I turned the ignition key, the fuel pump did not click. Around the same time I started having a problem where when going up a 20 to 30° hill I typically get a stalling/lurching problem, as if the engine wasn’t getting enough fuel. I also had a couple occasions where I’d start the car, it would run for 30 seconds or so, and then stall. It would restart after that. I googled the issue and my problems checked all the boxes for a faulty fuel pump. I just had the electric fuel pump replaced, but I’m still having that lurching gas starved problem on hills. Has anyone had this problem and figured out what the cause is, or have any suggestions of what I could try next to fix it? Could it be some fault in the electrical connection between the ignition and the fuel pump, or bad gas, or a fouled spark plug, even though they are fairly new? And why now, only on inclines?
Thanks!