Speed and reference senders?

["Salah Khan" <salah.khan@gte.net>]

Hello all,
I asked the dealer to diagnose the hard start problem I've had on my V8 (the
previous owner had the same problem: approx. 10-second cranks most mornings,
but sometimes not.  How cold it is outside doesn't change a thing.)   The
dealer retrieved codes indicating my speed sender is inoperable, and the
reference sender "might be" (?) intermittantly inop.  They would charge $650
to replace them, and cannot assure me there would be any improvement.
I am not familiar with these parts.  Could someone tell me what their
function is?  Will their replacement help the hard cold start? Would anyone
suggest I purchase them elsewhere and replace them myself?  (I have no
special tools, and I'm not a wrench.  But perhaps they just click in and
out...?)
They also mentioned that worn crank case and vent hoses could be involved in
the hard start. ($250 to replace them...)
As you might imagine, I would like to do my darndest to avoid having the
dealer perform any of these jobs.

Thanks for any advice on this.
Salah