In the online 2003 truck manual, service specifications page SS30 shows the gap as .043". I did see a troubleshooting page that reads .031". So I guess it depends on where in the manual you look.
Clifton
http://fsm.afraid.org/
http://fsmSS049–04.afraid.org/
SS049–04
SS–30
– SERVICE SPECIFICATIONS IGNITION (2RZ–FE, 3RZ–FE)
198 Author: Date:
2003 TOYOTA TACOMA (RM1002U)
IGNITION (2RZ–FE, 3RZ–FE)
SERVICE DATA
Spark plug Recommended spark plug DENSO made
Recommended spark plug NGK made
Correct electrode gap
K16R–U11
BKR5EYA–U
1.1 mm (0.043 in.)
Camshaft
position
sensor
Resistance at cold
at hot
835 – 1,400 W
1,060 – 1,645 W
Crankshaft
position
sensor
Resistance at cold NE+ – NE–
at hot NE+ – NE–
1,630 – 2,740 W
2,065 – 3,225 W