[///Manuel]

I got the same exact problem, my take is that it's a fuel pump return valve issue.
Got the fuel pump sitting, as soon as I get a chance, it will go in.
I'm almost certain it was related to my higher emission values as well.
Could also be leaky injectors. Regardless, it shouldn't be an expensive affair.

Note: It's more pronounced on cold days and almost imperceptible on warm days.
I hear some slurping sounds upon starting too coming from the pump.

 

[dj leethal]

I will look into it. Haven't driven her for a few days. It is quite cold too, so I will see what happens when I start her up today.