My truck has about 113k on it now and while I haven't had any injector issues I'm to the point of trying to buy them one by one (spread out the cost) and stock pile them incase I need one down the road. Everything I've found the seller wants a core charge, is it possible to buy injectors w/o paying the core charge? Reason being is it maybe 6months, 2yrs etc before I even need to change one out and most won't refund your money that far out.