I noticed in the past few weeks that my truck is smoking slightly at idle, more of just a haze really. I have 145,000 miles. Still seems to drive and tow well, dont think mileage has been affected. Anything to worry about?

 

I have been noticing my truck doing the same thing. Even when I have the truck idled up I get a light haze. I had a buddy with a Dmax that did that same thing, and it had a bad injector...

 

Smell the tail pipe and check the color.

Fuel smells like raw diesel and is an injector or air in the fuel and will be blue or gray haze, white if engine is stone cold. Don't idle it for more than a few minutes after it has the initial cooldown as too much raw fuel can wash the cylinder and cause problems. If your oil does not appear thin or increases in volume due to fuel dillution then probably not a problem leaving it alone. Buy a cheap oil sample analysis kit from a truck dealer on the next oil change to confirm fuel in the oil is in an acceptable range for peace of mind before spending four figures on injector work.

Oil will be blue and smell like burnt oil similar to the smell a car makes that burns oil.

Antifreeze can be gray or white and smells sweet.

It's not the end of the world unless it is bad. Without a catalytic converter a normal engine may show haze or smoke in headlights behind you.

Just some ideas.