'06 SCrew, F-150, 5.4, 2wd
Occasionally when I start the engine, I will see blue-black smoke from the exhaust pipe. Forgot, 85k miles.
Truck runs great otherwise, and the "smoke" doesn't happen all the time.
Is there some minor thing that can cause this, or should I be taking it in for warranty repair (Ford extended)

Thanks
Ken

 

Blue and black smoke is usually 2 things. 1. Your burning oil. 2. Your running rich, my guess would be that your running rich since it's only 85k on the motor, clean your Maf throttle body and air filter for starters. Then I'd look at your o2 sensors. Are you getting any check engine lights?

 

No check engine lights.
K&N CAI, the filter is clean.
The truck is getting the best mileage ever, 16+ combined.

Last night somebody mentioned the PCV valve as a possibility.

The truck is under an extended warranty through March, so if any major repair is needed, I want to get it done now.

Ken

 

Ok first for pretty much free I'd clean the maf and throttle body and see if it persists.

 

When it sits a while coolant seeps in to the cylinders. No big deal. And when your running rich its white with a little black.

 

Burning coolant is white and isn't normal that's a cracked cylinder or blown headgasket, not good! Burning oil or running rich is the bluish black smoke he's talking about.