i have an 2005 3.4 monte.for the past few days,starting the car for the first time of the day she will start normal,run normal for about 15-20 seconds then the rpms go a little haywire.they will go up to 1500 then suddenly drop to 400-500 and sounds like she wonts to die.she smelt like she was running rich before this happened.also the 3rd time this happened i gave her gas when she started to go nuts to keep the rpms up and white smoke came out of the tail pipe.after she throws her fit for 10-15 seconds she will run fine all day.i can shut her off and restart with no problem.its only on cold starts.any and all help to this issue is welcome and i thank you in advance.

 

You've probly got a gasket going out somewhere, that's what it sounds like anyway, the white smoke is probly from burning oil

 

i had a z 34 that acted a little similar. erratic idle at start and i just delt with it forever haha. but im positive it was the intake gaskets. getting a lot of extra air after your sensors makes it act pretty strange. i'd start with a tune up and go ahead and pull up the upper and lower intake and replace the gaskets. if its leaking antifreeze into the engine thats prob ur smoke

 

White smoke is Coolant being burned. Blue smoke is oil. Black smoke is obnoxiously rich mixture. If you're puffing out white smoke only on cold starts it's deffinately a gasket problem. When it heats up your gaskets expand and soak with their proper fluids internally but when cold they shrink again and some fluid gets let in or out. Expansion and compression on these gaskets is on a very tiny scale so you probably won't find the spot but it'll be easy to find the gasket and change the whole thing. My tips for gaskets is clean the suspected area well with degreaser drive her for the day and check the following morning for obvious leaks.

 

finally thru a code,o2 sensor bank 1.thx for the replies.