2006 Grand Prix problems.

[Perma]

2006 Grand Prix GT 3.8L

This has happened twice in about 3 weeks, I'll come to a stop and the car will shut off. It starts back up completely fine. I noticed yesterday when I came to a stop it revved up a bit and attempted to move. It stalled about 10 minutes after that.

I was driving home today and when I went to accelerate the car was struggling, I had the gas floored and it kept trying to accelerate harder but it wouldn't.

These are the two codes popping up:
P0300 - random/multiple cylinder misfire detected
p0455 - evaporative emission control system leak detected(gross leak)

 

[Rico]

Put a new gas cap on it

 

[Perma]

I understand that 0455 usually means gas cap, but would that cause the other issues?

 

[BillBoost37]

the huge vacuum leak may be causing the issue.

 

[Rico]

^^Yea like Bill says. Check the vacuum lines near the purge solenoid on the top of the motor and the one on the fuel pressure regulator.