Ls400 Engine (Pinking ) ?

[PJ1888]

Hi there, my name is Pete and i have a 1997 LS400 ON 178,000 miles.Have had it about 2 years now and it runs like a dream. However since i have owned the car, under acceleration ( especially from cold )the engine sounds as though it is pinking but dissapears somewhat when warm,although not completely.It did not bother me too much then but as time goes by it is very annoying.I phoned a Lexus dealership about the problem and he said it was common on alot of 300s & 400s and that it was the fuel injectors, but it seems a very risky chance in spending out on them if it may be something else.I dont really know anyone with any knowledge of 400s so here i am hoping someone out there may be able to help.Many thanks, Pete.