Check Engine Light

[Nolimit4]

I have a XG350L that has 40k miles and will be 2 years old this November. I've been very pleased until a weird problem surfaced. One day last week the check engine light came on coming home from work. I followed manual instructions for the check engine "Malfunction Indicator Light" which seems to deal with the exhaust gas related component. My dealer had the car for the first fix attempt and reported a "CODE PO446/PO441 OPEN CIRCUIT" problem. Their solution was to replace the "purge valve".

I picked up the car, the check engine light was off and everything seemed ok. The very next day I drove my 52 miles one way to work without incident. However, on the way home at night only 5 miles into the drive, the light came back on. Back to the dealer the next morning for them to attempt solution #2. The reported problem this time was "EVAP VENT CONTROL - MALFUNCTION CODE PO446." The fix was to replace the fuel tank pressure sensor. It was Friday night when I picked up the car and thought everything was good and the check engine light was off.

The very next morning I drove 2 miles to the gym and the light came back on. My dealer service shop is only open until 1 PM on Saturdays. When I went there they said they could not look at the car again until Monday morning.

I'm left scratching my head on this one. The other check engine light threads in this forum had different problem codes. Could it be that I just had a bad tank of gas? If yes, I have a 1/4 tank left. Should I burn that off first and then refill? If I refill, I would still need the dealer to clear the code. Correct?

Again, I'm scratching my head and running out of patience. I'm not pleased over the prospect of adjusting my vehicles so I can drop the XG-350L off and then only find out that the problem resurfaced again the next day.

Any ideas? Thanks in advance!!
Rob