E30 Zone

Hi , on my mission to get this thing to start a bit easier ive noticed that when it does finally go , and i if i remove the oil filler cap the engine nearly stalls and runs like a bag of spanners ,ive read somewhere this suggests an air leak as its creating a vaccum , if this is the case where do i start to look for it , ive tried to hit it with wd40 ,but no difference when doing it ,any ideas ????

You're getting things a little confused! Run like a bag of spanners, and nearly stall, is what it should do if you remove the oil filler cap.
The crankcase normally operates under a partial vacuum, and if you remove the filler cap, air is sucked in and through the breather pipe into the inlet manifold, where it weakens the mixture.

dont we do air leaks ??

thanks for that brian ,but would it not take a fairly serious air leak to cause problems starting from cold ,ive changed all the usual suspects ?