White smoke coming out of the exhaust

[Yeueb]

My 06 4.6 with around 141k miles has white smoke coming out of the exhaust, despite no signs of anything going wrong. The idle is extremely rough and it's very hard to even get the car to start and get up past 300 rpm for more than barely half a second. It's never had this problem before, and it even ran amazingly before doing this. The other night I was hanging out with my friend and just before I got to her street, the car died. Again, no problems at all running or getting started the whole night or weeks before. But the car did sit for about 7 years before I bought it 2 years ago. A couple weeks ago I just cleaned the inside of the tank, replaced the fuel pump and fuel filter (again), and it's ran perfectly since. I'm stumped and really really hoping I don't have to replace a head gasket. The motor is completely stock with nothing more than a K&N intake from the previous owner.

 

[StockishS197]

White smoke from the exhaust is usually coolant from a bad head gasket.

Any coolant loss? Does the exhaust smell sweet?

 

[whitmanink]

just check the over flow tank, if your loosing coolant than its one more sign pointing to the head gaskets,,
that would be best case,,,
worse case,, a warped head,, because so much coolant is getting in the A/F mixture its bogging down the motor even before warming up and expanding

you can also pull plugs ,, that will tell all

 

[cavero]

Does the exhaust smell sweet? Any cloudiness in the oil?