I have a 1998 1.9 Z3.
It's driving so badly I'm grinding my teeth!!
I had it diagnostic tested at a BMW garage who say there is a fault line on the fuel injection diagnosis that could indicate sticking valve lifters.
I have tried lubricant for valve lifters in the oil that settled it for 2 weeks, injection cleaners in the petrol etc but the [Oops!] ride comes back with a vengeance.

I'm looking at over 600 to have the lifters replaced. Should i expect this with BMWFSH and 42000miles?

Any hints, ideas welcome.

oil changes and flushes? Thinner oils? Products to recommend?