Get a reader and check the code. Without double checking. I think P0440# (440-449) is the Evaporative Emissions Control system, I think 445 is the most likely for a vacuum leak (Don't bother asking how I know this, NO I did not have one) same code you get when you forget to put the gas cap back on (not how I know it, but there was an On-Star commercial that featured that boo-boo).
(Ok, I'll tell you. There is a solenoid valve on my "new" towed that was sticky)
(Plus I have a low end reader, it just gives me the codes, so I naturally have a PDF file on the hard drive... And I searched it).