Just picked up a 92 si hatchback it has a d15b block with a z6 head it starts up and has difficulty holding a idle if not warm. I was told by the po the timing was off a bit? Would this fix the issues slight white smoke out exhaust no power when on the gas and a little misfire? What is the right timing to be set at? Thanks

 

It sounds like there are multiple issues with your car. Is your computer throwing any codes?

The difficulty idling may just be an idle adjustment, or timing related. You will need to check the mechanical timing (timing belt and gear alignment) to verify what the seller told you.

White smoke indicates burning coolant - which could either be a cracked block or a failing head gasket. Is the car consuming any coolant? Is there any water/oil mixing occurring?

No power could be a result of the aforementioned issues. Fix the timing first. The right timing has two components: mechanical and ignition. First check the mechanical timing as I noted above. You will need to take the valve cover off to expose the cam gear. Check the motor at TDC and make sure the marks line up. If mechanical timing is good, then check ignition timing with a timing gun. Google how to do this, it's not hard.

Report back when you've finished the above. Let us know how it goes