91 850i, it won`t stay running.

I have a 91 850i, before I had this problem it ran fine expect it was missing off and on
what I found was 2 plug wires were bad, so I upgraded all the wires and clean the
throttlebodies. Now I started the engine and the problem I`m having is it won`t stay,
it will run for a fue seconds then stall, I recheck my work everything is fine.
so what do you think the problem is?

Thank WE31