I have a 2001 Honda civic with about 200,000 miles on it. Lately the engine light keeps coming on, so I went to a place like Auto Zone to get them to run the code. They told me that bank one wasn’t firing properly and that I might want to change the spark plugs. I changed the spark plugs with the cheapest ones they had, well it still kept giving the same code. This time, three of the four banks weren’t firing properly. I change the spark plugs again with the most expensive one. Now Auto Zone is telling me that I might need to change the ignition coils. From what I’ve read, if the ignition coils go bad my car wont start. I don’t want to change something if I don’t have to. I don’t want to take my car to the shop until I kind of know what is going on.
An engine with 200,000 miles on it could very well have excess carbon deposits formed on the backsides of the intake valves. And this would definately cause a misfire condition. before spending money on coils you may not need, try this.
Purchase a can of SeaFoam Motor Treatment. Get the engine up to operating temperature. Remove the brake booster vacuum hose from the brake booster. Adapt a hose the will fit into the end of the brake booster hose and into the can of SeaFoam. Take a pair of pliers and pinch this hose off. Have someone start the engine and bring the idle speed up to 2,000 RPM’s. Now slowly open the pliers so the SeaFoam begins to drawn into the engine. When the engine begins to stall out pinch off the hose to stop the flow of SeaFoam into the engine and bring the RPM’s back up. Continue to do this until all the SeaFoam has been drawn into the engine and shut the engine off. After a half hour has passed, restart the engine and bring the RPM’s back up too 2,000 RPM’s until the smoke clears from the exhaust.
And just to let you know, the engine is going to smoke a lot when doing this, but it’s just the SeaFoam doing it’s thing.
Tester
I’d not say the Seafoam is a bad idea no matter what, but have you tried new wires? Or is this coil on plug? If it just has standard spark plug wires they should be changed too.
How did the old plugs look?
For this Honda and most other Japanese engines you need to put in the same NGK or Denso plugs that came from the factory.
Anything else is a crap shoot.
It’s coil-over-plug according to the info I found. No plug wires.
If one cylinder is misfiring you can swap two coils and see if the problem moves.
Have the valves been adjusted on a regular basis (every 30K)?
Next check the fuel injectors (swap if necessary), then a compression test.
The first time I changed the spark plugs, I used the cheap ones. I now have Bosch platinum spark plugs in my car. Changing the spark plugs however hasn’t solved the problem. They come out looking dirty and smell burnt.
I will try the seafoam this weekend and get back to you.
How do the plugs compare to these:
I would have to say maybe picture 11.
I would have to say maybe picture 11.
OK
From my previous post:
If one cylinder is misfiring you can swap two coils and see if the problem moves.
Have the valves been adjusted on a regular basis (every 30K)?
Next check out the fuel injectors (swap if necessary), then a compression test.