I've got the Service Engine light on in my 2002 Blazer,with a code that I'm told means Vapor Lock. So what does that mean??

Thanks for any help you can provide.

 

It would be easier to help if you were to tell us the code. Is it a p0440, p0442, p0446?
It may be a a faulty emission canister vent solenoid valve located under the fuel tank shield above the spare tire.
If it's a faulty valve it may not be venting the fuel vapors through the canister properly. If it's stuck closed - building pressure, if it's stuck open - always venting.