My car is a 518i manual E34 1991 M40/B18 engine.
I have to turn the key for a long time and accelerate to start the engine. When it is running the engine vibrates and when I accelerate it returns to normal.
Someone told me it was cold starting valve or is it the injectors which are leaking. The engine makes clicking sound when accelerating or driving uphill.
Does this car has a cold starting valve or is it another thing is not working well?
Which are the best spark plug to use?