You Do Need power plug adapter while traveling from Tahiti to Guyana.

Here is Why You Need An Adapter

The outlet and plug type used in Guyana are A, B, D and G and in Tahiti are C and E. This is how they look like.

Tahiti

In Tahiti, outlets of type C and E are in use.

Type C

Type E

Guyana

In Guyana, outlets of type A, B, D and G are in use.

Type A

Type B

Type D

Type G