87 Monte LS
305hp
74K miles

With the controls set to the dash vents, when the car is first started the heat and air is only being sent to the floor. After a period of time (10-20 minutes - time varies), the air will eventually start coming through the dash vents.
Are vacuums lines going bad? I thought vacuums either sucked or no suck. Could it be a small leak but yet over time enough vacuum is created to activate the actuators?I'm just making uneducated guesses.
Any ideas? If you think it might bevacuum lines, any help tracing the lines (as far as location) would be a great.

Thank in advance!

 

It does sound like a problem with your vacuum lines. I had a simialar problem but mine didnt work at all. When doing some research I found on the older models it has a vacuum canister that you might wanna look into.

 

Good idea right there, I would also check the cabin filter to see if it's dirty as it can cause some weird things as well.

 

Happened to me once. It was the pink and purple lines that run inside to the controls. They are hard plastic and 1 of them had cracked just enough to cause a delay. They are on the right sideby the a/c and turn quickly into the right fender and dissappear. Sometimes they are hard to find but they are there. Good luck!

 

Thanks to all for the responses. I'll let you know what I find out this weekend.