Hi I'm new to the forum. I just purchased the car (1985 300ZX NA 5-spd) a few days ago and I'm trying to figure out a problem im having. I have
replaced the old spark plugs and wires and everything, checked all the fuel lines and even the distributer looks new. When I go WOT it just doesnt
feel like its giving all that it has, it feels choked out and feels as if its dropping off in the upper RPM's. A couple of my friends have suggested
that it could be a clogged cat/exhaust system, but are there any other problems that it could be? I'm new to the Z world so please bare with me 
O and on a side note: The other reason why I know something is wrong somewhere would be because my friend beat me in his dads 2.2 cavalier last
night.
EDIT: I also forgot to add, in the morning when its cold and I go to start the car it has massive hesitations and I have to pretty much floor it to
get the car to stay running and then once its warmed up its fine. It sputters a lot and just acts like somethings getting choked whether its the fuel
system somewhere or the exhaust. Any help is greatly appreciated in advance, thanks again!
Welcome to the board, Z31Fairlady. Don't know too much about some of the symptoms you're having, but I do know one thing about cold starts. My Z would not start up cold without me keeping my foot on the gas for awhile to get it up to a reasonable temperature. Turned out to be the CHTS (Cylinder Head Temperature Sensor) which needed replacing.
Where is that located? And can I get that at any parts store?
CHTS or Air Regulator for Morning Symptoms
TPS (Throttle Position Sensor) or o2 Sensor or MAF (Mass Air Flow Sensor) for your Wide open throttle Symptoms. Replace the o2 sensor first, even if
its not the issue its probably time for it to be replaced anyway. Then either test the TPS with a volt meter or replace it. Then test the MAF (This is
an expensive part so you want to test it first)
It could be some other things too, but those are the normal culprits. Could also be a faulty fuel pump, or a fualty fuel pressure regulator for
instance, but is not normally the case, also it could be clogged cat as your friend suggested, but again is not normally the case.
If you havent yet, go get your injector recall done at a dealer, its FREE and they replace your Fuel Injectors and Fuel Components, that in itsself
may fix your problem, but if not at least you lose the risk of your car being burned up out of the blue becuase of a leaky fuel injector.
Also, visit z31.com/board for your technical questions, they can correctly diagnois most
problems fairly quickly, just be sure to SEARCH BEFORE POSTING.
Lastly, and don't take this the wrong way, but the z31 NA is not a fast car, and you could have very well have lost the race with the cavalier
legit.
z31 NA:
5 Speed Coupe
0-60 9.1
1/4 mile: 16.9
1995 2.2 Cavalier LS:
0 to 60 mph 9.4
1/4 mi (E.T.) 17.1 sec
All good advice and I appreciate it. But I won't take the last statement wrong. Besides, there is no way I lost by as much as I did when he has broken motor mounts and doesnt know when to shift. And when I said beat me, he was able to catch up and pass me like I was standing still. It was like a geo metro vs. a camero..........it was horrible. That's just not normal. And I know the car isnt the fastest thing out on the road but im just saying, it should be able to at least keep up if not pass up the cavy. It cant even keep up.
Z31fairlady, the CHTS is located behind the timing belt cover. Not sure if this is a part you can buy at an Autozone or Kragen, etc. I actually had mine replaced for me.
To elaborate on what Ford_Falcon said:
Purchase the CHTS from the Dealer, autozone will give you a Temp sensor (not the CHTS) if you ask for a CHTS from them. Oh, and the CHTS is an
absolute bitc* to get at, it is possible if you bend the timing belt cover a bit, but I warn ya, its in a spot thats not easy to get at.
Here's a link that briefly describes the location, and testing of the CHTS:
http://www.engr.colostate.edu/~radare/CHTS.html
hi
i did have the same problem with my z (i have an 87) check the time for the distributor