Random “hiccup” at idle when engine warm

[98civex]

I have a 98 civic ex d16y8 with 198k miles. Lately if I drive for a while (20 minutes or more), I’ll get a very random hiccup/slight misfire at idle which is not predictable. Some days it never happens.

I have new spark plugs, wires, cap and rotor. When I replaced cap and rotor I noticed oil INSIDE the cap, I’m guessing from a failing internal seal. Not much it wasn’t pooling or anything, but enough to notice. There was no oil around the cap terminals or rotor so I’m curious if that could still interfere with ignition in some way and is what’s causing the random hiccup?

Also I’m wondering if loose valves would cause this issue as well (they were last adjusted around 100k miles) or since that’s more mechanical if the problem would be more consistent and not so random?

 

[nd4sped]

Any fluid contamination inside the distributor can cause all kinds of ignition issues. From oil to water or condensation if the port is plugged. This is due to the additional sensors inside the distributor under the black cover beneath the rotor. The CKP and CYP sensors are very sensitive.

Put a new seal on the distributor shaft and gear that locks into the camshaft.

 

[98civex]

Any fluid contamination inside the distributor can cause all kinds of ignition issues. From oil to water or condensation if the port is plugged. This is due to the additional sensors inside the distributor under the black cover beneath the rotor. The CKP and CYP sensors are very sensitive.

Put a new seal on the distributor shaft and gear that locks into the camshaft.

Where’s the port to check? I’m going to change the internal seal and spray electrical cleaner on everything before reassembly. Is that a good idea to do? Also is there a way to test the ignition module through resistance of the terminals or no?

 

[nd4sped]

Where’s the port to check? I’m going to change the internal seal and spray electrical cleaner on everything before reassembly. Is that a good idea to do? Also is there a way to test the ignition module through resistance of the terminals or no?

Testing the ICM you will need to take it to your local auto parts store. Oriellys, Advance, Napa, etc still provide this service for free and most locations.

 

[98civex]

Testing the ICM you will need to take it to your local auto parts store. Oriellys, Advance, Napa, etc still provide this service for free and most locations.

Thanks. Should I spray everything with electrical cleaner after replacing the seal? And would it be a good idea to add a thin layer of dielectric grease to all the connections to help prevent corrosion?

 

[GlennH]

Dielectric grease is an insulator that prevents the conduction of electricity, while conductive grease has a degree of electrical conductivity. You want conductive grease on the connections. dielectric to keep out moisture. Many people misunderstand and incorrectly use these products

 

[98civex]

Dielectric grease is an insulator that prevents the conduction of electricity, while conductive grease has a degree of electrical conductivity. You want conductive grease on the connections. dielectric to keep out moisture. Many people misunderstand and incorrectly use these products

Right that’s why I said would it be a good idea to add on top of the connections after they’re all made to help prevent corrosion?

 

[GlennH]

Electrical conductive grease is designed to help prevent corrosion on metal surfaces within electrical connections