[Topless]

Agree an intake air leak is most likely. A failed MAF is also possible as the car is running lean. Clogged injectors are possible but unlikely affecting both banks.

TS guide for 2002 model 986:

DME 7.2 (2000-2002 Boxsters)
P-Code Bank RPM Range Reason Look for:
P1128 1 Idle Engine is running very lean and the fuel adaptation has
pegged its rich correction.
Intake/Exhaust system leaks; MAF not performing correctly; fuel
delivery components cannot deliver enough fuel.
P1130 2 Idle Engine is running very lean and the fuel adaptation has
pegged its rich correction.
Intake/Exhaust system leaks; MAF not performing correctly; fuel
delivery components cannot deliver enough fuel.
P1126 1 Lower Load
(Low RPMs)
Engine is running very lean and the fuel adaptation has
pegged its rich correction.
Intake/Exhaust system leaks; MAF not performing correctly; fuel
delivery components cannot deliver enough fuel.
P1133 2 Lower Load
(Low RPMs)
Engine is running very lean and the fuel adaptation has
pegged its rich correction.
Intake/Exhaust system leaks; MAF not performing correctly; fuel
delivery components cannot deliver enough fuel.
P1125 1 Upper Load
(High RPMs)
Engine is running very lean and the fuel adaptation has
pegged its rich correction.
Intake/Exhaust system leaks; MAF not performing correctly; fuel
delivery components cannot deliver enough fuel.
P1132 2 Upper Load
(High RPMs)
Engine is running very lean and the fuel adaptation has
pegged its rich correction.
Intake/Exhaust system leaks; MAF not performing correctly; fuel
delivery components cannot deliver enough fuel.