Just brought a 1999 Tahoe, went out to start it today and it backfired, maybe not a back fire but when I turn the key I heard a poof sound and some smoke coming from under the hood. anybody know what this is?

 

Did it ever start?

 

yes it does start, but every once in a while, when I turn the key it kind of makes a poof sound and then there is a small cloud of smoke that comes from under the hood.....seems to be coming from what looks like the carb?

 

Probably a a battery that is not fully charged or going south on you or a lazy starter, if the starter does not crank fast enough you will get what you describe even though there is nothing wrong with your engine.

What happens is that a slow crank during start-up can cause the motor to kick back against the starter as a couple of the cylinders hit on the compression stroke, kind of like what happens when you kick over a motorcycle and the start lever kicks back and injures you, if you had just kicked harder it wouldn't have happend.