possible timing problem on 2001 Toyota RAV4

my sister's rav4 suddenly starting running is if it had dropped a cylinder (idoling extremely rough, obvious loss in power) all 4 spark plugs appear fine, fuel injectors are fine, anybody know if somehow the electronic timing could be off and how it can be fixed?

Asked by for the 2001 Toyota RAV4
MIL light is on. What are the trouble codes?