I bought my 92 GSR a few months ago and ran into a problem that seems common among these cars…hesitation around 3 to 5 grand. I started with the most likely things like plugs, wires, distributor, ignitor, coil, timing, fuel supply etc. Everything was either new or tested good. I noticed that this problem would arise once the car was in closed loop and would occur more frequently on hot days, going down rough roads and after making turns. I found that I had a bad ground for the map sensor. (although when tested in my garage voltage, ground and resistance in the circuit all tested good) My guess is that there is a slight break in the ground wire where the harness enters the firewall underneath the brake booster. What I did (since I have an abundance of wiring harness at the house) was cut the entire map sensor harness connector off, sodered the 5volt supply and signal wire of a tps connector to the vehicle harness map sensor wires. I grounded the green and white wire to the harness bracket on the left side of the fire wall. I then set the base idle and timing, clear the computer, and let the car idle for about 20 minites before I went for a drive. Hope this is any help to people that have lost countless nights of sleep chasing this problem.
A corroded battery cable did a number to my db2…
That was one of the many problems I had too. I see that rust likes to build up on the negative terminal cable where it mounts to the body under the battery tray. The other major problem I had was leaking injectors, so bad it was filling the o2 sensor harness connector with gas! I had a set of obd2 injectors with new seals laying around so I used them. The obd2 injector harness connectors are alot easier to deal with. I hate those damn retaining clips on the original ones.