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Multiple misfires according to Autozone type code readings. Runs good when cold and always idles okay. A little hunting that levels out quickly at start up. The misfires happen after warmup, and always under load primarily beginning in the 2000-2500 RPM range. If I can get the auto trans to kick down, it used to go like heck, but now the misfires aren't going away as easily at higher RPMs...or at all.

The history: over a yr ago the multiple misfires jumped up from out of nowhere. After finally replacing the spark plugs with NGK, the problem stopped...for only a few days, maybe a week, and returned to doing this especially on hotter summer days. Cool days I could control it with the throttle and RPMs. Before the plugs I had assumed this was a fuel issue and changed the filter plus ran multiples of cleaning treatments/premium detergent gas though the car. The car went from never being over half a tank low to always running the tank to empty, so I thought it was fuel related until the plug change fix it temporarily.

So last month the problem increased dramatically. It runs well when not up to temp, but poorly when warm. Last month I ordered NGK wires and Honda cap and rotor. Replaced the air filter too. The car ran perfectly for almost 3 days and now it's back to being almost intolerable to drive again. So I picked up a jy distributor and put it in today. Identical problem. No change.

The car has been hot a few times over the years and a slow loss of coolant was discovered but never seen to leak, so I guess it's going into the engine. Not going into the oil. It always looks normal.

So what are the most obvious causes of this? If it is a head gasket, why does it perform well at high RPM under load? I've searched all the way back through 2012 threads and seen the same issues asked about but have never seen the issue solved. Just the question about the freeze frame codes and then the thread is dead. Freeze Frame is a new term for me that I understand is a deeper code acquisition. But surely someone has experience with this and it's most common causes?

Thanks for any help.

 
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If you find this situation, you MUST replace the spark plugs AND the plug wires together.

If you only change one part, the remaining tracks will burn through the new parts.

 
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Hmm, that makes very good sense. That picture is a telling story.
If that's the case here, I sure hope those new plug wires can be remedied with some cleaning.

 
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If this is in fact the problem, don't even bother. It's already ruined.

Like I said, you MUST replace the spark plugs AND the plug wires together.

I didn't say a word about cleaning any part of it. You can't clean this damage.



"Hear me now, believe me later."

 
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I'm going to buy them again with new plugs. I think I'll plan on doing this tomorrow if they're in town.

 
Rep Power: 518

Did you pull the plugs out and look for this carbon tracking evidence as shown in that picture?

I like to know when my guesses are confirmed as true, prior to tossing parts at the car LOL.

 
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The parts tossing has been continuous for a while now. Not impressed with Honda at this point. I'm not convinced this is the problem. But new parts will tell the tale. I pulled the plugs last month and saw no obvious tracking. That was about when the wires were ordered. I ordered a distrib O ring, wires, cap and rotor. Distributor was leaking a good amount of oil. Checked the plugs for condition and saw no obvious tracking, but wasn't really looking hard since I figured wires were the next try anyway. Didn't see anything like that picture, but that's probably an extreme case.

The only other thing not mentioned was that when I replaced the plugs last year, I replaced the cap and rotor once already, but with box store parts.

 
Rep Power: 518

This is really not a "Honda" problem at all.

These types of problems can happen to almost any engine, any car.
The real issue is in not being able to find the root cause and solve the problem.


=====

Something else----I keep forgetting this because Hondas original plug wires were so darn good I almost never saw any real problems from them:

The plug wires that most parts stores sell are often low quality. They tend to leak sparks from between the plug boot and the plastic tube, or burn pinholes through the side of the plastic tube.

 
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^^ If sparks are leaking between the bottom boot and plastic tube, you probably will not be able to see it.

I check for this with the engine running, lift the wire up and watch for where the sparks come from down in the plug hole.

 
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The wires are NGK as are the plugs. It's only had the original Honda and then these. Cap and rotor were parts house type.
The replacement plugs/wires will remain to be NGK.

I pulled the plugs and one plug has a big black spot on the side of it down low with tracking spots as in that picture. Looks like this might to the answer I'm looking for!

 
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Oooooo yeah that looks ugly! You should be able to see the matching tracks in the end of the plug wire mate.

The sparkplug socket you install the plugs with, make sure the rubber insert is clean and dry! (brake cleaner seems to work well for me)
Sometimes leftover dirt and grease can be the cause of the tracking, it gives the spark a path to follow.



I always thought NGK was a good brand of wire, even if they had a few issues. The blue color is just a plus LOL

 
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Yeah, the tracking was gray on the boot. So far so good. Drove it up to temp a couple of times today and tried to lug it up hill where it used to sputter I think I felt a bobble once, but I'm not positive. The car has a load more power than I remember it having. I'm loving it so far.

 
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The car's running great. You nailed the diagnosis.
Thanks.

 
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Yay!

 
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i have a 97 ex that seem to be doing the same thing. when im going down the interstate at 90mph the rpms run right around 4000 and the car doesn't have a problem. but when i let off the throttle to about 3500-3750rpms the car seems to stutter and shake a little. the codes were coming up just cylinder 4 misfire and i had already replace the distributer cap, rotor button and all the wires, the plugs are maybe a month old but were not replaced at the same time. i took the car for a 140 mile trip today and if i was in the 3500-3750rpm range the engine light would start to flash until i either raised the rpms or let off completely. when i got back from my drive, i put the car on the computer and came back up with cylinders 1, 2, 3, and 4 all misfiring, along with cylinder 1 too lean, and the EGR flow was insufficient. i pulled the plugs to make sure they were getting fire, and they are all getting plenty. i read this thread and went back out to check and theres no tracking that i can see, i am using 7mm autolite wires with NGK plugs and do not see tracking on either. i am however using dielectric grease. there is one tiny tiny mark on one spark plug, but i don't feel any texture with it and don't see a matching mark in the wire boot

 
Rep Power: 518

Did you disable your EGR to see if that makes any difference?

 
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I haven't done that, where is the EGR located?

 
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IDK enough about your engine to do any better at this.

If your intake manifold is like this one in the picture, you can see where the EGR valve should be. Unplug the wiring connector from the valve and drive it for a couple days or however long it takes to decide if it helped or not.

If disabling the EGR valve helps the situation with the stutter and shake feeling, then the EGR chamber probably needs removed, clean out the passages of carbon debris, clean out the gasket, and clean out the holes in the intake manifold runners where the holes in the gasket are.




HTH

 
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There want really any noticeable difference, but I cleared the codes on the car again and started it back up and almost immediately, the light came back on. I put the computer back on it and it came right back up with cylinder 2 and 4 misfiring

 
Rep Power: 518

So it sets misfire codes without having to drive it?

I'll suggest start with a compression test, post your results

 
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I adjusted the distributor and it seems to be all set, I'll drive it around a bit and let you know how it goes

 
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My car ran fine at high rpm but got hot too. Was a head gasket that eventually failed. Had to shave the head and install a new gasket. If it's not the wires, plugs, distributor, fuel or ignition timing, I would suspect a head gasket especially if it's losing coolant and getting hot sometimes. The problem sounds intermittant so it's hard to diagnose properly. The only other thing I can think of is make sure your ground bolts are clean and have good connection. It's essential for the ecm or computer and other components. A rusty ground connection or a bad connection in the wiring could cause intermittant spark trouble at lower rpm but at higher rpm it has higher voltage possibly so it may just get a good enough connection. Those are the two things I can think of that could be causing your problem.

 
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A compression test may or may not show a problem as my head gasket would seat properly a lot of the times then mess up at other times with my car. It seemed to mess up more as it got hotter if that makes any sense. It's still worth a compression test though. I think a leak down test would help a lot too if the compression test shows everything to be fine.

 
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Glad I found this thread my 04 is misfiring on 2,3, and 4. I'm going to check the plugs tomorrow for this.