1994 Infiniti Q45 Bad Shaking Problem

Hi,

I am at my wits end trying to repair my Q45. Here is a break down of the symptoms.

1. It shakes badly when idling
2. Sometimes it won't start as if it is not getting fuel

What I have already done:

1. I replaced the mass air flow sensor - used part
2. I replaced the fuel pump - new - now it starts
3. I replaced all 8 fuel injectors - new - still shakes

Now it starts but it still shakes very bad.