Crazy reving

for some reason when i get into my car from say the grocery store after i have been in their for like 20mins and go to start my car it revs up to 3k and down to 250 rpm's and up and down for about 30secs-1min. then all is fine?? runs perfect and everything. if i try to drive it right away it wants to bog down. but if i wait for a bit, it stops reving up and down and drops right to 700 rpm's where it should. could this be the fuel pressure regulator? or damn, i'm not sure. any help would be greatly appreciated. thnx

Fast idle thermo vlave more than likely. Try taking it off and see if you can clean it. There is a plunger type thing in there that regulates the are comming into the throttle body when the throttle body is closed.

damn its crazy u know all this. thnx man:bigthumb: