Ford: ford ranger idle problem, solenoid valve, ford ranger

Question
Dear Ken;

Thanks so much for your help.  I found what I believe is the Idle Air Valve.  I disconnected the two wire plug and removed the solenoid valve.  It was pretty much carboned up.  I did not have any carb cleaner so sprayed it with WD40 and shook it up.  When I replaced it, the truck started.  Loped a bit and settled into a nice low idle.  I drove it shopping around for about thirty miles and found the idle to be so quiet, I had to open the driver door and listen.  Idle nice and smooth.
When I was replacing the valve, when it was tight, I tapped it lightly with the wrench and a strange howling sound issed from it.  I had heard this noice before on occasion and learned that if I 'goosed' the engine it would go away.  This time, I turned a small black knob on the outside of the valve and the sound whent away.  I did this three or four times.

My question is, what the heck is the black knob and is it now out of adjustment or what?

Ken, it is running fine.  Thanks so much for your help.  

steve balme


Answer
Mr. Balme,

The black nob is to adjust how much air intake comes in. If it starts idling rough again, just turn it a 16th or so until your idle comes back. The carbon build up could be because you are  burning a little too rich. Glad that everything worked out for you. Hope this helps and if you need further assistance, please do not hesitate to contact me again. Good luck.


Ken