Inspect and test all the following listed below and get back with some results
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.
Note: If it doesn't apply disregard.
April, 30, 2010 AT 12:30 AM
No the coils don't need chassis ground
January, 4, 2011 AT 2:16 PM
These vehicles are semi notorious for intermittent mechanicaly sticking injectors. This will cause surge, missfire, stalling ect. This is somewhat maddening. It is worse when the engine is fully warm on a hot day. There is no easy way to diagnose this. Prosses of elimination. I personally have the same problem I have 25 yrs. Master auto tech with L1. I have a 88 Z24 pickup myself. I'm in the prosses of looking for rebuilt injectors. New ones cost 240-290$ each!