It starts up strong, but where the RPM's would normally smooth out right away, they drop so low the engine almost dies, then revs up to around 1600 RPM's and then finally normalizes. Thoughts?

 

That sounds like a number of things. Even though I don't have a Z32 my 280ZX was doing this for a while. It doesn't sound like anyhting major to worry about, after I went through and checked the gap on my spark plugs, regapped any that were off, and got my fuel pressure regulator working, the car seems to fire up and not bounce around like it used to.

 

Only had it a week, so haven't done much at all to it yet. I was thinking of ordering some NGK Iridiums and running Seafoam through the fuel system - maybe that'll take care of it.

 

seafoam

also look thru these links. you should be able to find what the culprit is there

 

probably a vacumn leak as well, you can spot those very careful, get a can of carb cleaner and start your car, spray the can over different areas of the car and listen for the throttle to rev up.

YOU CAN ONLY DO THIS FOR A MIN OR SO! YOU HAVE BEEN WARNED!

Carb cleaner is very flammable, but used in this situation can be used to spot check vacumn leak areas then you can come back and check the connections, do not try to pin point but can be used to narrow down the area, great for boost leaks too.