Pontiac Repair: Evaporative Emission Control system, gand prix, gas vapors

Question
QUESTION: I have a fault code PO442, Control system leak detected. (small leak). With the engine off and the gas cap off I can hear coming into the gas tank. I can disconnect a elec. part on the intake next to the MAP sensor and it stops. I want to know what part to check or replace to correct the problem. I hope you can help. Thanks. Chuck

ANSWER: Hey Chuck:
what model car is this and year? A P0442 is REALLY REALLY hard to find. depending on the model of the car I can tell you what common leaks are. I don't know what type of noise you are refuring to in the tank... The part on the engine is the purge valve it allows the engine vacuum to pull the Gas vapors back into the engine to burn them instead of venting the vapors into the air.

---------- FOLLOW-UP ----------

QUESTION: Sorry, I did not provide enough information. I have a 99 Pontiac Gand Prix with a 3800 engine and the noise I here in the gas tank is like air flowing into the tank and when I go to put gas in, it blows it out and clicks the pump off. I can disconnect the wire to what looks like a selnoid on the intake part of the engine and the noise in the tank stops, but I don't know what the part is or if it's the problem part.Thanks again for your help
Chuck

Answer
I think your going off ona tangent here.. that part on the engine is the purge valve. it's not the cause of the problem. Like I mentioned before a p0442 is VERY hard to find. a few things to look at are the seal on the gas cap and the flange on the top of fule filler pipe. that flange has a tendency to distort and on some years the filler pipe actaully rots out.. you could have a purge vent valve bad also that is on top of tank. some times a 442 code needs to be checked at a shop with a "smoke" machine where the system is sealed off and a smaoke is injected into the evap system and then the leak can be found.... good luck :}