well this reputable mechanic aint no better than the other. im sure the box he is referring to is the air cleaner/filter box. wow he goes from saying its just the valve spring collapsed is the whole problem, now its "I think u got a bad injector" I wouldn't buy the injectors even it is a partial fix to the problem, simply bc its an electrical part and once its installed, there is NO refund for it, so by him borrowing them injectors, there aint no telling how many times they were installed and how old they are. I honestly think ur getting the run around from this supposed top notch mechanic. I don't give a damn how many recommendations he has, he aint worth the salt that drips from a donkey's bottom lip! its been what 3wk now that he has "diagnosed" it to a bad valve spring and now u need numerous other parts? I think he is full of the white speck on chicken poo, oh its chicken poo too.
I'm sorry for your misfortune but I would have to agree with charles........seems really funny to me that all it needed was 1 valve spring 3 weeks ago and now all of the sudden you have parts missing.........this guy sounds like a TOOL! best of luck and stay on him like white on rice!