Runs for 5 or 6 min. and then dies. will not restart till next day then same.
 

I have a 1987 928s4 and i have noticed over the last week i would start the car runs fine for a few minutes then stops. then car will not restart till the next day after . then same thing.
any thoughts.

Those are some semi-strange symptoms.

Does the engine seem to run well while it's running or does it seem to labor?
Have you ever released the flex plate pressure or had the flex plate pressure released?
After it runs for that little bit, and you try to start it, does the starter labor to turn the engine over? When it dies, does it die suddenly, or does the idle slow down until it dies?
Does the car have an automatic transmission?

The car dies sudden. as if it is a fire issue. but i did not want to just start swapping parts. it runs perfect and idle is at 600. i was thinking defective temp 2 sensor but not sure it original. Auto trans.

when the engine dies and i try to start it there is no labored start . it spins fast and free. some time it will fire one time but then quit. Tach is jumping so i think i have signal from the ref sensor

It sounds like CPS, but God help you if it is and it's an original. Replacing mine had my swear jar overflowing with fistfulls of $ones. An intermittent problem on warm start with no issue on cold start, along with a bouncing tach are classic signs of a bad CPS (crank position sensor).

GAS-AIR-SPARK. You can start with the basics. Pull the hose off the fuel filter going to the front and see if fuel is coming out when warm starting. If you have gas, that eliminates that part of the equation. Then see if you have spark. You may need a helper for these tests.

From your answers then, I think we can rule out TBF. That's probably good. :)

My thoughts would be either Temp II, which is a temperature related sensor to both the LH and the EZK (and the easiest and quickest one to replace) or as husker says, the Crank Position Sensor which can sometimes be a bear to wrestle with. CPS sensors can be contrary and sometimes intermittent as they warm up with the engine.

thanks everyone, pulled the csp today and the end was swelled and discolored. i have a new on on the way.

Glad you were able to get it out. Hopefully, that'll be the end of your issue.

just a update. car is running like new . new temp II sensor and a cps and that did the trick.

Thanks for the confirmation and the update. Drive it like you stole it.