Ford F-150 2000 starting problem and idle reving

I have a 2000 Ford F150 V8 with 130,000 miles.

Up unitl about 6 months ago. When I turned the key it started right up, I barely had to complete the turn of the key.

Then on cold days sometimes it seemed like I had to hold it a little longer sometimes, but not always.

Then it started on really hot days too.

Then about a week ago it had a real hard time. I would have to turn the key a couple times and it seemed like it was not getting fuel. Then eventually it would start. But even after driving for awhile. It when I would put it in park the rpms would dip just below 1000 and then just above. Like I was taping the gas.

I have been taking it back and forth to the mechanic multiple times over the last 6 months and they think I am nuts because onve you drive it a while. It starts right up.

they put it on the 'computer' and everything comes back normal.

They said they think it may have something to do with it sitting and then the gas prossure bleeds off?

Anyone any ideas?