88 911 only starts sometimes
 

my 1988 911 will only start now and than,if it fires?,it will stay running than after the key is turned off it won't fire back up, after it sits a day or two it will fire back up? what is the deal? thank you if you can help, I would love to drive her,the weather on the coast is great now!

Could be a couple things, but I would start by replacing the DME relay first. If that doesn't fix it, then I would look at the reference sensors and the cylinder head temp sensor.

I have done all of that,now what?

Have you checked the basics like spark, coil, plugs, distributer cap etc?