Need help with my money eating Ml270cdi,when I bought it it had injector knock under load but only when warmed up.had injectors tested and 1 need repair had it done by garage then ran worse than ever total missfire garage told me it needs,throttle body,,bought new no change ,,it's had everything including Ecuador,still has missfire,,I have took it out of garage now as he's has no idea ,,this is now bleeding me dry ,,,need it fixed as I love ,,any ideas would be appreciated