While driving i have an issue where the vent will be blowing but at certain RPM's it changes to blowing through the defroster. Then it blows back through the vent. I am sure it is a Vacuum issue. Any idea of where to start? It is getting annoying.... Is it hard to run new Vacuum lines???

 

your vacuum reserve tank has a leek or a line is loose

 

I have checked most of them and thats why i am wondering if i should just run all new lines.

 

Does it happen when you are excelerating,or just when it chooses?

 

you are loosing vacuum some how
their is a check valve on the vac supply line to the reserve tank that my not be working

 

seems to be only under acceleration.

 

yes your manifold vac drops on acceleration
so any thing that is vac controlled will go back to a neutral position on acceleration

 

So it is a Manifold vac problem not a canister vac problem?

 

How many miles are on your motor?

 

It's a system vacuum problem. If it were a manifold vacuum problem it would act the same all the time. JMO

 

all the vac is suppled by the manifold to the reserve tank under the right front of the bumper
if you have a leak you will loose vac in the system as you accelerate cus you manifold vac drops

 

the motor has 149,000 miles on it

 

Somtimes when a motor starts to loose compression it will have vacuum issues more noticable when you accelerate,but 149,000 is not many miles,just trace your vacuum system and seeif you have any leaks,or hear any,it is proabably small.

 

X2

 

it has nothing to do with the motor
its a leak in the vac system or reserve tank

look under the right front bumper for a 6" round or oval plastic tank with vac lines coming from it the follow all the lines check for cracks