just put a new caliper on my car. Bled the brakes and have great peddle until I start the car and then I have excessive peddle. Any ideas? Been working on it again and if I unhook the vacuum line from the booster while the car is running I get my peddle back.

 

I dont want to sound like a smart *** but the rule of thumb is always replace both calipers at the same time.
Not saying this is your problem but you could get uneven braking by only replacing one caliper.

As for your problem I would say your power booster is on the blink.
Not sure how you would test this without replacing it.

 

Sorry shoulda said I rebuilt 1 front and both rear at the same time I put the new one on.