[88Targa]

Of course it's frustrating when you get an error message that could mean many things. I got this message and thought "oh, it's some stupid malfunction". Actually, dealer service department found that a mouse had nested on top of my engine and had chewed through the wires to the purge valve sensor! Sadly, resulted in a $2,000 front wiring harness repair but insurance covered all but $100. Guess what I'm saying is that sometimes this message is real, it's just that it's like your computer freezing and you don't know why. An OBD II device could probably help you get more info. But glad you figured out the gas cap thing!