My car has an hks Bov ( blow off valve) on it and it always runs perfect after a cold start but then after a good 5 miles it starts to make a flutter noise. I have tried replacing all my vacuum line but that didnt work. Anybody know something? Thanks

 

go back to the stock bpv. HKSs have had problems on these cars time and time again. From what I read a long time ago, from HKS themselves, the placement of the bov on Cobalts, where they need to be, causes to bov to get hotter than it can handle due to engine heat. Your not the first person to have issues with a bov on a TC and you certainly won't be the last.

 

I have had it in the car for a while though with no problems, I heard you had to grease them? If not I'll go back to stock

 

I have one in my car from HKS and it works fine. I did have to use a softer spring to make it work, but i have had it that way for over a year and it works great.