Dipstick grommet from what year car/transmission ?

 

So this code has 0 to do with smog or how the car runs or anything like that? I thought this had something to do with the massive cloud of smoke from the exhaust or the foul odor inside the car which smells like foul exhaust.

 

What code? Evap?
This post is old.

 

P0455 - large evap leak.

I've got a few things going on with the car but it sounds like it doesn't really relate to exhaust clouds or smog?

I'm not an expert so just trying to figure it out....

 

It does have to do with emissions. The fuel vapor type, not exhaust gases. And it does affect the efficiency of the engine.

 

If the purge valve is the leak it will not idle right. Especially after fueling up.
What are your symptoms?

 

other than the code and "check gas cap" message on DIC, foul exhaust odor, cloud of smoke from exhaust after 3k rpm pull...however does not smoke at all on the freeway...

 

You have just the one code for large evap leak? That is not causing the smoke under load. Are you consuming oil? Does the car accelerate OK?
The smell could be from the EVAP.

 

The VENT valve might cause problems while filling the fuel tank.
The Purge valve has nothing to do with a vacuum leak and nothing to do with idling after a fill up event. It might cause a hard start and/or P0171/P0172.
Exhaust fumes in the cabin is not a minor problem, things like death could result.
I don't know which basket case hhrumadbruh is talking about, so I don't know it talking about the flex pipe is warranted.

 

There are a few jury rigs mentioned, in this very thread even!