very rough start
 

i have a 1995 Z34 it has a 3.4 v6 in the cold mornings it starts very very rough when it warms up it runs great can some one help me with this problem

RE: very rough start
 

Wrong section to post it, but I'll answer it anyways, or at least to the best of my knowledge, haha.

If the engine just sounds rough, and has a slightly higher rpm than usual at idle its most likely piston slap. I'm guessing this is what the problem is, becuase you say after it warms up, it goes away.

I have a 1998 LS, and I have the same problem. Different engines, but it doesn't matter with GM at this point.

Anyways, the 3.1 and 3.4 are notorious for it in about any weather usually, while the 3.8's have it usually just when it cold.

If you want more information, you can go to this site.
Like a Knock

The websites says 99 and up, but my old 93 grand am had the same issue.

Its possible you might have something else, but i'm assuming not.

I hoped this help, but if not, maybe another member will have a better answer.

RE: very rough start
 

Hi Les! Welcome to the forum.

The 3.4 in my 99 Grand Am did the exact same thing. Even the first day I drove it off the dealership lot brand new in 1999.

The service manager and the mechanics at the dealership told me it was piston slap and that it's normal for that engine. They told me that if it doesn't go away after a few minutes, then bring it in to get looked at. Since it's the sound of the pistons slapping before the oil has a chance to work it's way through the engine.