kjb

My truck all of a sudden started to blow black smoke, suck down the gas and run rough.
I have replaced the o2 sensor, spark plugs, vacuum lines. Still have the same problem. It is 3.0 V6.

Any suggestions would be great.

76ANTHONY

kinda sounds like a tuning problem. when was the last full tune on this truck?

kjb

I have done most of a tune-up. No cap and rotor yet.

abecedarian

when do you get the black smoke? all the time, slow or fast acceleration, etc?

kjb

as soon as it starts. sems to be dumping way to much fuel..

kjb

Is there a fuel adjustment screw. Seems to be getting to much fuel to bog down.

abecedarian

check the flapper in the air flow meter to see if it's stuck.
may also be the cold start injector or switch. you may try unplugging the connector on it.
does it start okay when cold but starts smoking while warming up?

thook

The airflow meter is a good start. Run a search on AFM testing. There's also the FSM manual stickied on the front page of this forum.

If any of what abe suggests passes, you might also check the fuel pressure regulator. There is a actuating vacuum line runnging to it. Pull that off and see if there is fuel or vapors in there. There should not be. It would be the internal diaghram has begun to leak.....or, from the symptoms you describe, has just all the sudden failed.

kjb

Thanks guy it was the MAF flap. I think this site is great!!

KJB

abecedarian

welcome aboard!

(oh, and it's afm, not maf. we have 'air flow meters' not 'mass air flow' meters, but it's all good.)