Idle problem: 280z FI
 

Ok lets see if I can explaine this in a some what logical manner.

The car runs fine b4 it warms up, idle is perfect. If I dont take it out and run it it will continue to idle as expected. When I do take it out and come to a stop light take it out of gear the RPM trieds to drop to 0 then catches and reves up and downfor a few seconds. Some times the engine dies most of the time it does not.

Any Ideas?

check your timing. You may be advanced way too much.

If it is advanced too much (should be 10-12 deg BTDC) and you can't adjust the distributor back far enough to bring it within spec then your oil pump shaft was installed one tooth off.