Puff of black smoke on first start of day

[TazMan]

Hello everyone. I just bought a 99 3.4l Grand Am with 110k. The engine runs and idles perfect. I can't even tell it's running without looking at the RPM's or hitting the gas. Yesterday on the first start of the day, I noticed a very small puff of black smoke. I turned the car off, started it back up, and it was fine. It hasn't happened again since. Should I be worried?

[Superdave]

black is it running rich, i wouldn't worry about it unless your fuel economy goes to crap..

[geoffinbc]

It may be a sign of injectors leaking. You may have had a fuel puddle in the intake manifold. If it continues all the time then get it checked out.

[nixtux]

Have you tried running some seafoam through it? And/Or taking it out on a open road and giving it hell? Assuming it's carbon build up which it might not be.

However when my Intrepid would do that I'd just fill up (89) and add a can of seafoam. Take it out and do a few hard runs up to 90-100MPH. Around 80MPH a smell like no other would fill the cab for a sec (during 2nd/3rd shifts at 6500RPM) and then everything was good after that.

Granted that isn't a GM car but anyway that's what my old mechanic would tell me to do. Which I never had any issues with the motor in my Intrepid. Everything else went but that motor is still strong and kicking at over 180,000mi (3.5 SOHC.) I was a young 19 year old when I bought that car so you can imagine the punishment I gave it. I was a bad driver then. Thank god for the cutty otherwise I'd likely be dead!

I passed the same methods on to my Cutlass except I never ran the Cutty over 84-5MPH. Fill up drive 5 miles to the interstate and just WOT it off the exit. Merge on the next exit. WOT it again home. But I've never taken the Cutty over 84MPH, EVER.