cruise?  On deceleration?<<

Thanks for your response.  Gray smoke, and thick.  On Acceleration only.
Especially from a standstill, but can happen after I am moving and give it
more gas.  Sometimes I barely have to depress the gas pedal and it starts.
If I let up on the pedal it stops.  Then it may happen again when I give it
gas or it may suddenly run fine for a bit.  And when I say giving it gas, I
mean slowly and lightly.  Seems to start happening after it warms up.

White smoke?  Gray smoke?  Black smoke?  Smokes on acceleration?  During cruise?
On deceleration?

And I don't mean going fast.  It recently started knocking really bad and
smoking like crazy.  It happens mostly as I start off, at a certain point it
will suddenly happen.  Then it might run ok for a while, then go back to
this knocking-smoking thing.  Sometimes I can hardly get going at all before
the knocking and smoking starts.  I have to really ease off the gas until I
get some momentum going.  Seems like whatever handles the timing just hangs
up.  I don't know.  Any ideas?  Thanks.