First off, Hello everyone! This is a great site and I finally signed up for it. anyway, back to my question...
I drive a 1990 300zx n/a. I recently purchased it and have noticed a few things with it. When I'm shifting in lower RPM's (around 2500) I am noticing some type of lag that last about a half second. I have cleaned out my throttle bodies. I have a new pop charger. New Labree exhaust system. New NGK spark plugs. New fuel filter. I'm not VERY mechanically inclined so this is probably going to be difficult for me to figure out. Any help would be great. I also feel like (since this is not my first Z32) that I'm not at "full power" even when it stops lagging. This may all just be in my head because of this lag issue but I would like to further investigate. My car only has 78,000 miles on it so I would presume it should be running beautifully. Thanks for any input you guys can send my way!

 

Good start. Test the resistance of your injectors just to be thorough... they're probably fine but one that's starting to go can cause similar problems. Also read http://www.twinturbo.net/nissan/300z...pages/pep.html and consider those options.

 

I had my injectors looked at. I might give it another look though. I will definitely be checking into those ideas from that link. Thanks a bunch!

 

Could also be timing, so I'd check that if you have the means. Cleaning electrical connectors and applying dielectric grease is never a bad idea as well.

 

ok ill have a mechanic check that out. I wish there was a good mechanic around here... when I get that cleaner, where exactly do i spray it? I probably sound like a moron. oh well thanks for your replies!

 

Just get electrical contact cleaner, an old toothbrush, and dielectric grease... disconnect electrical connectors, spray onto the leads, brush any corrosion away with toothbrush, apply dielectric grease, reconnect.

 

the injectors can be checked for <20 dollars. Buy a multi meter and set it to ohms. 10-14 means the injector is good, check that yourself. Mechanics are not to be trusted, especially when you say there isn't a good one in your area.

 

I just wanted to update everyone just incase this problem happens to you. I got my rear diff fluid changed out and this seem to help a lot! I still notice a slight lag but it definitely is much better. I will check timing shortly. Thanks for the help guys.

 

ok so I guess I was wrong. The problem happens a lot when it is cold outside. It's not quite as bad when the car has been running for a while but is still noticeable and makes me angry! I talked to the nissan dealership and they seem to think its the vaccuum hoses but wanted to charge me 90 bucks an hour to find out. SCREW THAT! I guess i'll wait around untill I can find a decent mechanic in my city. Any suggestions would be great thanks guys!

 

TwinTurbo.NET -> Search -> "boost leak tester"

 

the only problem is that I don't have a twin turbo

 

And when a TT isn't in boost, those leaks are called vacuum leaks. The problems, their diagnosis, and solutions are the same.

Problem: bad airflow readings due to air escaping or unmetered air entering

Diagnosis: pressurize the system and listen for leaks which are audible with the engine off

Solution: replace hoses that have leaks

 

oh ok thanks a lot man! I will have it checked and post back when done! thanks again!