[0] When were they made and stuff?
1984-1989 models were made. The first 13 were produced in early 1983 as factory race cars, regular production started with #14. You can find all the production data you want in the 300ZX registry at z31.com/registry.
[1] My oil pressure and/or gas gage(s) act funny
The fuel level sending unit is prone to getting dirty and giving inaccurate
readings. It is an easy task to remove and clean it. It is accesable
through the hatch in the floor of the hatch area, under the carpet and
insulation. Remove the cover and the plate from the top of the fuel tank.
The sender is right in front of you, just yank it out. Clean up the
contact with a solvent and make sure the float still does. Replace
and your problems are gone. Hopefully.
The oil pressure sending units are also notoriously bad as well. They cost about $40 from a dealer and are easy to replace. It is located on the passenger side of the block, directly behind and level with the oil filter. It's a simple matter of out with the old and in with the new. It is advisable to do this while the oil is drained and the filter is removed. It is extremely easy to replace if the starter is removed as well.
[2] Part or all of my digital dash is out
See z31.com/dash.shtml
[3] My hatch and/or gas door dosen't work
The hatch/gas door cable is sometimes known to go bad. If your hatch
or fuel door don't open some or all of the time, look under the toolkit
in the back of your car. I'll bet you see some nasty looking rust huh?
Notice the lever type thing the cable is in. This lever rusts in place.
If the rust is not too bad, oil the pivot of the lever and hope that
helps. If not, you'll need to take it out and clean it up. The cables
are very, very difficult to get off of the lever. If you pull hard the
plastic ends of the cable will break. Best is to get a new lever from a
junkyard and cut the old one off the cables, very carefully of course.
If you break the flange off the cable coming from the handle up front,
simply slip the remaining attached part of the flange into the lever,
the sheath of the cable is only pulled, so it'll stay put nicely.
To get your cable into a new lever, file off the little bumps in the
slots which retain the cable. These prevent the cable from vibrating
out of the lever, but also prevent you from removing the lever without
breaking it or the cable.
[4] Injector recall?
Nissan recalled all 84-89 300ZXs because the injectors were manufactured
with seals that leak over time. This results in fuel leaks and eventually
engine fires. Take your car to any dealer and they'll replace all underhood
fuel system components for free.
[5] AHHHHH! My Z leaks water like a faucet!
See z31.com/leaks.shtml for the
story on this one.
[6] 300ZXs have timing belts?
Yes they do. Change it every 50k miles and you'll be fine.
See z31.com/tbelt.shtml for
the low down on changing it.
[7] My clutch pedal flops to the floor!
Your clutch master cyclinder is clogged. Replace it and the slave
cyclinder now. Driving your car like this will destroy the throwout
bearing, which requires removal of the transmission to replace.
[8] Why do my rear tires tilt inwards at the top?
There is considerable rear camber built into 300ZXs. It is not adjustable.
Excessive camber is caused by a number of causes, including(but not
limited to) worn wprings, bushings, accident damage, rust weakening, and
a number of other causes. You can fix it by moving the outboard
adjustment bolt down a little. Displacing the bolt downwards by an
amount equal to its width will produce approximately one degree of positive
camber.