Dave The kit I have is a Volvo and it has a fitting for the frequency valve to do just as you describe. That way the frequency valve is included in the flush. I have used this on several systems that sat for a long time and it definitely helped. However, I also discovered, by accident, that Marvel Mystery Oil works miracles in the k-jetronic system. With the k-jetronic recirculation the system is thoroughly cleaned and without any real trouble. I can tell you that one car I had was really a slug, ran rough and had sit a long time. I replaced all the fuel parts from the pump up to the warm up regulator but the system showed varnish, etc. I put in some MMO and every time I started the car it ran better until it was smooth as silk. About 2 weeks and 2 tanks of gas. I still run some in the system every spring. Harold McElraft - 3354