I had the same thing happen earlier this season, the jets felt weak even though the pump sounded fine. First thing I did was check the filter, and sure enough, it was way dirtier than I thought. After a good backwash (I’ve got sand), the pressure improved a bit, but still wasn’t great.
Next, I pulled the pump basket and found a little wad of leaves stuck right where the line feeds into the impeller. Cleared that out, and the difference was huge.
One other thing I learned: even a tiny air leak on the suction side can make your jets feel sluggish. I went over the pump lid O-ring and union fittings with silicone lube and tightened everything up. Since then, the pressure’s been back to normal.
So I’d check in this order: filter, pump basket, impeller area, then hunt down any possible air leaks. Nine times out of ten, it’s one of those.