harsh shaking after start

[steagle]

just recently, i started noticing that after i start my LS, a few moments pass and then i feel the car shaking harshly from side to side. this lasts only a couple seconds, and doesn't seem to return during idles or successive restarts in a short period of time, but damn it feels like a mini earthquake in there. i'm bringing the car in to the dealer on Monday to check out several other things, so hopefully i can tackle this problem as well, but in the meantime do any of you guys know what's going on?

 

[executivechef01]

hey i get that as well i have an 04 lse its annoying my friends call it "the seizures" i think it might be the kkm intake but i dont think it would affect only my car, im gonna by the recharge kit and see if something changes and eventually in about a week or so itl be going into the dealer pending removal of my intake so my warranty isnt voided.

 

[Beamer]

Mine does this too from time to time, it did it before I got the KKM and intake tube so I would not think its related to that. It goes away after a few minutes and only returns here and there after the car has been sitting from day or more.

 

[2001LS8Sport]

Can you throw a fuel pressure guage on it and watch what it does? I'm betting it's fuel related.