**CLIFF NOTES: Drove car in rain for first time and it was hesitating and stuttering**

Purchased a 95 z28 a few weeks ago.

Tonight was the first time I have had it out in the rain since I have owned it. It was raining hard but not a down pour. After about 10 minutes of driving it starting hesitating and stuttering, not terrible but it was very noticable.

I was just about a minute from the house so I drove it home and into the garage. I have a moroso CAI so I figured it was sucking up water from the CAI, so I unbolted it and checked it out but it was bone dry on the inside of the intake as well as the filter.

I put the filter back on and started the car and revved it and the miss was completely gone. I took it back down the road for about a mile or so and I couldn't get it to reproduce what it was doing earlier.....

Anyone have any idea what happened or what is going on ?? Don't want this to be something that is going to happen everytime it rains so looking for solutions.

MODS: (incase u need this info)
moroso CAI
4.10 gears
tb bypass
52mm TB
smooth elbow

 

Sounds like your plug wires may be the issue. Are they original? Check for arcking.

 

Car has 75,xxx miles, I am almost positive it is the original plugs and wires. I have a set of headers on the way and I planned on doing plugs/wires/coil while changing the headers also.

Too check for arching u just wait til it gets dark outside and pop the hood and start it then check for sparking by the plugs and wires, correct ?

 

I would replace the coil wire first(week link).A GM wire should be fine.Cheaper to buy the whole wire set,but might be a quick fix.Did you notice the car missing at high rpm's? then try the coil wire first.My02.

 

Its funny u mention that. It did have a miss up top a few days ago and I took the coil wire off the coil and noticed the coil tip was corroded (sp?) so I took a wire brush and cleaned it off. That was like 3 days ago and it ran perfect with no miss or problems anywhere.

Yesterday when it was in the rain it was missing through all the rpms. But now that it was dry today I took it out and drove it for 30 minutes and never had a problem out of it.....

I just dont see how it raining can cause this problem, makes no sense to me.

 

OK,now, are you loosing any coolant?The water pump sits just above the distributor(optispark).When that #$@#%(&**^#@ starts leaking out the weep hole,that means you need a new waterpump.Your distributor has had time to dry out,so when you start up again,everything is fine for a while.Also,if the rain or puddle splashes up to it,this can cause some misfireing.(Car washes are a no no with the under carriage spray they use.).Hope this helps.(Did you also clean with a small wire brush the inside of the coil wire?)Really ,a new coil wire will bring a smile to your face.

 

Your wires are likely to be the reason. Water gets everywhere and it is "road water" full of impurities which makes it conductive. It facilitates the arcing of a compromised wire. As suggested, try the coil wire first. You had played with it and maybe the seal is not as tight now as it should have been.
This is almost classic text book case of bad wires so I would not be too worried.
Yes, the optispark is also sensitive to water but I would start with wires.
I hope this helps.

 

its your wires bro. i can vouch by saying the EXACT SAME thing happend to me. its weird i know, but whenever it rained, the poor car was missing like a ****. just get a nice new set of wires, maybe a new distributor along with it if thats old too, but its definitely the wires.

 

Bad plug wires. They arcing when wet. Been through it myself. Get some MSD 8.5 super conductors and be done with it.

 

Thanks for all the help everyone

Hope it doesn't rain again before my headers come in