Need code discriptions

'94 Buick Century. 139k miles. 3.1 LTR. V-6. Got codes. Please advise. Thanks. GMBW.

1) PO134

2) PO321

3) PO342

4) P1403

5) P1404

6) P1405

7) P1640

8) P1650

Missfire and evap problems.

Instead of me trying to explain all of this, let me refer you to the diagnostic charts for this engine. If the link gets removed or something, autozone's website www.autozone.com has online repair manuals which are pretty accurate for this particular car.

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/0f/1b/46/0900823d800f1b46.jsp1)