Welcome to the addiction...
Answered some of your questions above.
Here a list of things to look at. I'm sure I missed few but here you go. Frankly, to me, $17k is high for a 91 in this condition and miles that potentially needs work.
Known issues for the ZR-1, some related to higher miles some not.
Injectors - 90-92 must be replaced.
Vacuum leaks to the secondary throttle system.
Secondaries operable?
Ingnition coils and wires replaced?
Timing chain noise at start (normal to a some degree on 90's)
Starter, does the car start consistently
Oil leaks especially the pan and oil cooler lines
Fuel pumps, have they ever been replaced?
Is it throwing any engine, abs or body codes (SES light on?,multiple possibilities here)
Are any DIC lights on. (Multiple possibilities here as well)
Is the adjustable shocks system working
Windshield delamination
A/C functionality (compressor is unique to the Z, cooling capacity lower)
Power switch functionality and keys (are there 2)
Transmission syncro'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
C4 Issues
Head lights operable
Radiator blocked or simply clogged, electric fans operable
Wheel bearings
Suspension bushings
Condition of all door, top and hatch seals
Glass roof cracking
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
Radio 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)
Good luck
H
