Did this a while back over on the other forum.
It all depends on what it is that you are looking for. If you don't work on your own cars and you want a fun weekend car that is reasonably reliable you will need a car that has been upgraded with at least some of the major known ZR-1 and C4 issues already addressed. If your like me you enjoy wrenching on the car and the challenge of fixing everything. I look for a solid car at a bargain price and do the work myself. To me that's a fun weekend.
I'm sure I missed few but here you go.
Known major issues ZR-1 some related to higher miles some not. But don't assume because your looking at a low miles car these won't exist.
Injectors have they been replaced, plan on replacing original 90-92 injectors, they corrode from ethanol in modern fuel, even on low mile cars.
Vacuum leaks, a high idle is a give away. Could be anywhere on the engine.
Secondaries operable, do you get full LT5 power. Is the SES light on? Will the engine easily rev beyond 4K rpm to 7k?
Ingnition coils and wires replaced?
Timing chain noise at cold start (normal to a some degree on 90's)
Starter? Ask if there have been intermittent starting problems.
Oil leaks especially the pan and oil cooler lines
Does the engine smoke or burn oil (normal to a small degree at startup on 90's) All LT5s burn some oil.
Fuel pumps have they been replaced? These can go bad on low mile cars stored for long periods.
Is it throwing any engine, abs or body codes (multiple possibilities here, SES light will be on)
Are any DIC lights on. (Multiple possibilities here as well)
Is the adjustable shocks system working? Again a dash light.
Windshield delamination. Edges will have a smoked or frosted look. Does it have a ZR-1 windshield with the cutout at the base of the glass in front of the driver.
A/C functionality (compressor is unique to the Z, cooling capacity lower)
Power switch functionality and keys (are there 2)
Transmission synchro's, (first gear is always noisy) shifter alignment can mimick synco problems.
Clutch functionality (they all let in high, was it ever changed)
Egr system on later models
Engine mounts, not easily checked.
C4 Issues
Head lights operable
Radiator blocked or simply clogged, electric fans operable, are engine coolant temps normal with the AC on?
Wheel bearings
Suspension bushings
Condition of all door, top and hatch seals
Glass roof cracking or crazing
Instrument cluster functionality especially the tach (tends to read high with age) also note the lighting of the cluster.
DIC button functionality
Steering wheel excessive movement, is the knuckle loose.
Radio and speaker functionality (especially speaker amps) and antenna
Sport seat functionality (transmission, switches, pumps and bladders)
Door window switches
Door window lifter and internal rattles
Fuel tank bladder collapse (results in small capacity)
Differential noise (whine)
Have fun...
H
