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Spark Plug Wire Pops Off

I have a 96 Honda Civic that I recently received a misfire code (check engine light) for 2 cylinders. When I popped the hood, I found all four plug wires partially popped off the spark plug. I reattached and started again and then found 2 plug wire off-seat. The plugs are only one month old. I then retorque to specs and tried again. Engine ran rough and later found one plug wire off-seat. I replaced all the plugs and the engine ran rough but wire didn’t come off-seat. Any ideas? Should I change the plug wires? Is there something more serious?

The problem might be with the PCV system.

At the bottom of each spark plug well in the valve cover is a seal that seals the well from the top of the head. If the Positive Crankcase Ventilation system isn’t operating correctly, the crankcase pressure builds in the spark plug wells and pushes the spark plug wires off because of how they seal to the valve cover.

Make sure the PCV system is operating correctly.


When was the last time the wires were replaced? Sounds like a worn set of wires. The seats on the end of the spark plug wires is not holding the spark plug well. And may be the wires are damaged internally, increasing resistance to the plugs or preventing spark from reaching them all together. Get new wires.

I changed the plug wires and that solved the problem. Good news was they were lifetime warranty and failed after 3 years but they were free. These are Bosch plug wires and its the second time I have had to replace them. Not very reliable plugs IMO.

I was going to replace the PCV valve but I see that it is tricky to access. Do you get it from the bottom?

I once tried a brand of spark plug wires in my old Camry that the clips on the ends of the wires kept coming off the wires. The clips were crimped to the wire ends and when they expanded to clip over the spark plugs…off they came!

Air can leak where oil might not. The seals around each spark plug --valve cover to cylinder head o-rings–could have hardened and cracked. Inspect/replace those seals.