I've got a 98 Camaro which is loosing AC airflow out of the vents when accelerating lightly. When I'm stopped, or in the driveway the airflow out of the vents seems good, however the AC selector setting for "Face/Feet" at the same time does not work at all for the AC mode. No air will come out of the floor and face under the AC selector in addition to the airflow fluctuating issue.

I've replaced the vacuum storage tank and the check valve next to the PCM which did not change anything.

The Vacuum line leading into the HVAC unit from under the hood does not hold pressure if you blow air into it, but the other vacuum lines held pressure.

What do you recommend next to check out and what should I expect? Thanks so much..

 

have you downloaded a factory service manual yet? brb

 

go here click the 98 svcman to download factory service/shop manual. https://www.mediafire.com/?40mfgeoe4ctti

 

sounds like you have a vacuum leak somewhere between the underhood connection and the heater/ac control inside the cab which could be the problem.

 

Thanks for getting back to me.. Yeah, I have the 98 service manual for my car, which is why i took a chance and replaced the check valve and vacuum storage. Not sure what is going on, but probably will pull out the hvac control and check the hoses behind. I thought someone on this forum might have seen this problem before. It's such and old car most of them are in the graveyard. mine only has 70k on the odometer and no rust. hoping to drive it for a while longer on the weekends...