Hello all,

i have a 1994 Z all stock, have just replaced plugs, cap, rotor, and opti and when i drive in the rain the car starts to idle bad when i let off the gas but seems fine when I'm on the gas. it only does it when its raining or the roads are still wet. any ideas on what might be causing this?

 

did it do this before you changed all this stuff, or you changed it because of it?

 

if you just changed all this because of the idle problem, i might check and make sure your not getting water in your engine. i would also check the opti vent tubes. i think that year had them hooked to vaccum.

 

Did you also replace plug wires? Old wires and moisture/humidity can cause arcing & misfires.

 

94 Opti is unvented = no vacuum or air supply lines.

 

didn't do work myself but im pretty sure that the wires were not replaced, have also noticed that i keep getting a slight knocking and pinging when i press slighty down on the gas almost like i put crapy fuel in but i always put 93 in it, so im not sure if wires would cause the problem with the moisture and the knocking and pinging or not.

 

You may have cross-firing on the wires, which might produce knock. The amount of timing error on a cross-fire might exceed the ability of the PCM to pull timing in response to the knock sensor.

Open the hood at night, in a dark area. Look for arcing on the wires and around the coil and distributor. If you don't see arcing, spray a small mist of water on the wires and see if that causes arcing. Don't spray anything on the distributor.