I have an 03 stock Z with 80k miles and lately it's been running rough when the engine is cold. It will start up and run really rough and shake bad, like it's running on 3 cylinders. No engine light and this problem is intermittent. It does not stall and after a few minutes it runs fine.

Dealer said they cannot determine what is wrong unless it runs rough at dealer, maybe have to take it there for a few days, gonna suck.

what could it be?
Thanks for your help

 

I have a 2003 350Z as well 64,000 miles and it does the same when i drive it right after i turn it on. So what i do i let it warm up for around 5 minutes and then its fine after that. It's the psi level that goes down on mine.

 

Fernando, what do you mean your psi level goes down on yours?

Any idea how this problem can be fixed, I need to sell the car soon, can't sell it like this.