Chrysler Repair: 2003 PT Cruiser poor fuel economy, poor fuel economy, bosch platinum

Question
QUESTION: I have a 2003 PT Cruiser with the standard engine and A/T.  Recently, my fuel economy suddenly dropped from its normally mediocre 24 MPG to less than 20 MPG.  I frequently get a check engine light and have since I bought the car new, but can normally clear it after refilling the tank to >1/2 full and reinstalling the gas cap.  My dealer says this is a very common problem for 2003 PT Cruisers due to the design of the fill neck.  This time, however, I’ve received a P0441 error code (purge flow) instead of the generic emission system errors that point to a faulty gas cap.  I’ve replaced my air filter and gas cap, used injector cleaner, replaced the plugs and checked for leaking hoses.  The engine idle is still smooth and there is no loping or surging.  Why have I suddenly lost 4 MPG of fuel economy?  Please help.

ANSWER: u need to get the 441 taken care of its part of the system that used fuel vapor in the gas tank to burn  so right now its not pulling the vapors from the tank its its suppose to.
Plus what spark plugs did u put in ? champions i hope.

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

QUESTION: I put in Bosch Platinum +4 plugs.  Is this emissions problem something I can deal with, or is this a dealer-only issue?

Answer
u should have put champions in  now u will have issues like u have with bad gas mileage on top of the check engine light issue. No i doubt u will be able to do anything with the check engine light this will involve testing out the evap system for leaks or non working parts. U can take it to a  regular shop see if they are lucky and have a scanner that can run those sorta tests and correctly figure out what is wrong or take it to a dealer and have a better change on getting id fixed correctly the first time.