So I have a holley 750 DP on my 383 its about 3yrs old with maybe 600miles on it recently ive had a random 2k idle issue you can start the car up with idle perfect at 800rpm after driving it will slowly work its way up to 2000rpm idle even if u turn tje idle down on the carb sometimes after the idles turned down after driving a while the idle will come back down to the point it will wanna die I turn it back up to 800rpm then keeps workin its way back up to 2k .... I shut the car off and start it back up it idles fine till you start driving then works its way back up... its my weekend car and within 2 days of driving it this issue poped up any ideas why

 

check for vacuum leaks with carb cleaner, around base plate. intake gaskets, tubes, etc