Smoking 4.0 on startup & acceleration

[88_Eddie]

VEHICLE: 2000 Explorer 2wd auto - about to hit 198,000
ENGINE: 4.0L SOHC

i've noticed on start up and acceleration that I'm getting some smoke out of the tailpipe.

driving down the road, no smoke at all. but if i stop at a light, when i press the gas to move again, i sometimes get a puff of smoke. no smoking at idle though.

it's not overheating, there's no white smoke or sweet smell and no milk in the oil. so i dont think it's a cracked head.

my oil temp and coolant temp are both normal, right where they should be.

from what i've noticed, it's either black smoke or blue smoke. hard to tell from inside the car. it sorta smells like carbon though, so i'm leaning towards black smoke. plus, i've noticed that my gas mileage is a bit off.

i've read this means a fuel issue, so i need some ideas of places to start. i figured i'd take off a spark plug this weekend and see if i need some new plugs and maybe remove the upper intake to see if an injector is bad.

thanks in advance for the help!

 

[88_Eddie]

tttttttt

 

[RonD]

Could be fuel, "black smoke", engine temp(ECT) sensor might not be "telling" the PCM(engine controller) that the engine is warmed up so it is running the engine rich all the time, there are 2 engine temp sensors, one for the gauge and one for the PCM, but not sure on the 2000 4l.
The Air Charge Temperature(ACT) sensor also control fuel/air by temp.
Clogged fuel return line can cause excessive pressure at the injectors
O2 sensor problem
Blocked air filter


"Blue smoke" could be valve seals or rings.

Idle allows fuel or oil to build up in cylinder, so at take off you see the "smoke"
Acceleration "smoke" could be either fuel or oil as well, obvious richness in fuel and higher vacuum pulls more oil past seals.
Both would effect mileage, and exhaust parts, i.e. cat converter, so best to find the issue.

Have you checked for any "codes"

 

[88_Eddie]

havent checked for codes yet. that may be my next step.

the cats and 02 sensors are all factory, so it wouldnt surprise me that they were wearing out now that i'm over 198k