I had a similar problem, which I kept "solving", only to have it
reappear again.  My guess is your starter solenoid is failing.  As it
fails, it becomes increasingly sensitive to any slight under-voltage
conditions, temperature, etc.

There is a "hot start" relay fix which is good if you are on a tight
budget, but probably only will delay the inevitable fix: a new starter.

I bit the bullet and just had a new starter installed (about $300 w/
tax & labor) -- worth my peace of mind to not get stranded
somewhere.   Got tired of playing the "will it start this time"
roulette... :-)

On Sep 11, 2006, at 8:59 PM, Woody Halsey wrote:

> A couple of weeks ago I declared victory when a new ignition switch
> seemed to have solved my problem (engine turning over without firing);
> but a new problem has now cropped up. I turn the key ...and NOTHING
> happens. If I hot wire the starter (from the alternator, with the key
> turned "on") the engine roars to life. But - sometimes anyway - just
> turning the key yields no result. Anyone have any thoughts?
>
>
>
> Woody
>
> 83.5 V'gon
>
> Haverhill, MA
>
>
>
>