I have a GMC sonoma how can i figure out the vin or the year?

Look at the vin on the windshield plate, why is this a problem, also there is a MFG plate on the door or pillar lt ft door. What does figure out the vin or year mean, also.?

im trying to figure out if my engine is a "W" or "X" or "Z", and the year also

In some of the older repair manuals I own, there is a section in the beginning of the book that shows you how to decipher your VIN #. I haven't seen many of the newer books so I don't know if they still include that info, but if you have a repair manual for your truck and your VIN # ( like Max said it should be on the dash under the windshield on the driver's side.) you should be able to get that info you need. If the VIN plate is not where it should be that might be cause for some concern if you bought the truck that way.

Do I understand you have a truck and do not know the year, is it registered? As mentioned if you look at the vin, the 10th digit is the year the eighth is the engine code.