I have a 1987 Chevy Celebrity. When I start it i have to give it gas rite away or it dies. When I drive it I have to stay on the throttle for about five minutes (includeing stop signs where i hold down brake at same time. When parked the idol runs really high. Once in a while it drops real low then kinda up n down in between. I checked for a vaccuum leak but found none. What am I missing? Does anybody have a repair solution?