thank you for your reply S-class, the idle is to low and I have gone threw the clean out procedure. I have another idle control valve(original) that was to high at idle, I changed to this one and it was good for a year but now goes to low and will some times allows the engine to stall on rapid slow down, as it dips below 400 rpm. I thought there was away to change the depth of the plunger to change the idle value?