is thethrottle switch making contact at idle ?
that's super important.
Assuming no intake leaks,
running stronly on all cylinders ,
no exhaust leaks,  and all that...
I can usually get them to idle steadily with tweaks on timing, throttle
switch, AFM screw,
and air bypass screw on the TB.
if idle rpm does not changein a fairly linear manner turning that screw ..
somethin' ain't right ..possibly the throttle body itself.

I have found up to 8 tiny air intake leaks too.

other stuff too.
hearing and seeing what the idle is like ....
'may' help someone nail it ..
and IMO, not anything like actual hands-on careful inspection, testing,
and tweaking adjusting will.

as a technician..
tell me the symptom..
giveme the keys , and I'll get back to you after doing the above.
Unless it's running on 3 cylinders or something ..
'mostly' hearing/seeing it run won't help a lot.

nothing like 'hands on' thnoughtful diagnosis..
even if one is not an expert tech ...one can find loose things, corroded
things..
things out of adjustment sometimes, and so on.

some people won't even just LOOK first ..
LOOK with eyes and brain ..
is that hose junction looking tired or weak ?
any vacuum lines tired ? ..
etc. etc. etc.

On 8/21/2013 8:15 PM, Jeff Palmer wrote:
> Hi everyone. I've been following the thread about the relationship between the throttle body and poor idle (I hope i have that right?)
>
> I'm wondering if my lousy idle is the same as what others have experienced.  I took two short videos that I was hoping someone more knowledgeable could take a look at.
>
> Is it easier for me to email the video or to post it to youtube or something?
>
> You can see that it surges a bit (100-200 rpm in this example, sometimes a bit more) when the van is in Park.  Drop it into gear and all is well.
>
> I have a 1985 automatic with a 2.1L Boston Bob.
>
> Thanks as always
> Jeff