Three problems American Standard’s own service sheets cover.
Not sure this is your faucet? See how to identify your American Standard cartridge without a model number, or how to find your brand and model.
Low pressure, worst at full hot or full cold
The cartridge inlets are clogged. Shut off the water, remove the cartridge as in the cartridge guide, and clean the inlets and manifold. If flow is weak everywhere, start with the aerator or spray head screen.
Leak at the base of the spout
The spout O-rings. On pull-downs, disconnect the spray hose first, loosen the 3 mm spout set screw, lift the spout, replace and grease the O-rings (Pekoe kit M962648-0070A, Quince M964175-0070A), and reassemble.
Pull-down hose leak or spray head stuck in one mode
Check the seal washers at both ends of the hose adapter. Hoses are model specific: M922367-0070A (Fairbury, Colony Soft), M922367-007220A or -007150A by flow rate (Quince), M964448-0020A (Pekoe); the Beale hose and spray are sold as one assembly, M964450-0020A. A spray head stuck in spray or stream is replaced as a unit with the handle off (Fairbury M950242 series, Quince M952249 series).