buying a new '92 300ZX twin turbo, idle problem?
 

Checked out a '92 300ZX twin turbo last night. Car is ridiculously clean and seems to have been meticulously maintained. Owner bought it about 10 years ago and has put ~2000 miles per year on it himself. Currently has ~96,000 miles.

Owner says the car has never seen snow and rarely seen rain and I believe him.

The car seemed to startup without issue an run great. Floored it a few times and seemed to have plenty of power.

There is a distinct "whoosh" noise when giving it gas (even low RPM, not heavy accelerating) - the owner says that's the quiet OEM exhaust. Didn't sound like a bad noise, just something I noticed. I've only driven 1 Z before, and it was a non-turbo with a loud exhaust so this "whoosh" might be completely normal. Comments?

Finally, the only issue I saw is after driving for 10-15 mins with the AC blasting it was running rough at idle, idle seemed to be dipping. Owner said that happens on occasion and turned the AC off and had me give it a bit of gas and the idle smoothed. Drove it a bit more and idle seemed good. Shut it down and started it back up up 5 mins later and again it seemed good. Does this sound like a possible fuel injector on its way out, or possibly something else minor?

Current owner said he had 1 injector replaced himself a few years back, and the original owner had 1 replaced as well. Seems to be a common issue with these cars.

I think the owner is asking a very reasonable price, especially because of the condition, so a bad injector isn't going to stop me from purchasing.

Any other tips when checking out these cars?

Thansk in advance, and hope to be a Z owner soon!

This wonderful "whooosh" you heard is normal, this is the fan clutch
for the idle it sounds like a sensor, but you'll find real mechanics here too respond more precisely :)
nice to meet you btw, hope you'll join the z community

I'm in the club! Here's my new baby:

http://www.techav.com/misc/300zx.jpg