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Hi everyone,
This is my first post and actually my first civic. It's a 98 EX coupe 5spd. Here's the issue, it'll run but then when it warms up it misfires and will jump the misfire around from one hole to the next at times. Has anyone experienced this and if so, does anyone know how to fix the issue? I greatly appreciate the knowledge any of you have. I've thought of coil, distributor maybe, or even ECU. I doubt its the plugs or wires since it jumps around but then again, I've not pulled the plugs to see what they look like, nor do I know the last time it's had a tune up. I could be way off base since I've not owned but a couple imports.
Thanks for your help or advice in advance.

 
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P0308 would be strange because that's not a valid code number at all for a 4 cylinder engine.

Got any more details?

 
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I wasn't sure about that number either the "p0308" but thats what I was told. However, any code with 03 anything has to basically do with the ignition system on the car anyway from what I understand. All I know is that it'll random misfire after it warms up. Only other thing I could think of is having a bad engine or body ground. Thanks for replying ezone!

 
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If P0308 is what someones code reader said, throw away that code reader because it can't be trusted. Try a couple different (brands) readers.
Basically? No. Every individual fault code number has a very specific description and definition.

P03xx series might be related to ignition system but that includes things like CMP, CKF, TDC, crank sensors, camshaft position sensors, knock sensor, circuit fault codes, cam sensor correlation codes (these can set when a timing chain jumps or stretches too much, is that still even ignition related?), there's 100 different generic codes from P0300 to P0399 (I'll grant you that not all possible numbers are used by every manufacturer) plus there's also "manufacturer specific" series like P13xx and P23xx and more, plus they have added hexadecimal number ranges and additional 2 character sub codes. Literally 100,000 possible code...and it's expanding all the time........
Sorry, I got far away from 1996 technology here LOL

Can you FEEL it or hear it run poorly when it acts up?
Do try to describe how you can make the problem act up, the way you are driving, load, throttle position, RPM, road speed.....
Got video?

 
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Now it's not starting, I just bought it yesterday and I drove it on the trailer. Soon as you turn the key, it's like the battery just went dead. I just bought new NGK plugs, pulled the cap off the dist and all looks fine even has a brand new coil which doesn't really mean anything from past experience. It seemed to start fine like the guy told me it did but then after it runs for 5 to ten minutes, it starts to misfire.

 
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Everything electrical goes dead? Dash goes dark, no lights?

Clean up all the cables and connections to bare shiny metal (take apart, use a wire brush or file or sandpaper), same for clamps on cables (cheap clamps stuck to corroded cables are notorious for bad connections), follow the ground cable to the body and to the transmission, make sure those are nice and clean and shiny

 
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I'll try all that. Thank you ezone, I'm going to make sure it has spark in all cylinders to rule out the coil being bad as long as it's a nice blue spark and not weak and yellow. But to answer your question, everything still works, I was stating it "acts" like a bad battery. When you turn on the key to crank it, it is bright, then you go from acc to start and goes straight dim. So i'm starting to think it could be a combination of bad battery and starter to begin with. Then I'll tackle the part of the initial question about the misfire. Thank you my friend.

 
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Technical details are important!

Voltmeter testing, ammeter testing if available, voltage drop testing......battery charger, jumper cables to a running car, etc.

A locked up engine can make a starter act bad too (extreme example, but I've watched a person replace more than one starter before he figured it out)
Color of visible spark is meaningless. How large a gap the spark can jump across is what's important.
If spark can jump across an air gap of 10mm that means the coil has the ability to provide roughly 30kv.


{voltage (kV) = 3 x spark length (in mm)}


Testing WHILE the problem is present is also important....

 
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Thank you Ezone for all of your knowledge. I take it as invaluable. Especially when viewing your stats on spark. Driving dirt late models if you had a nice blue spark it meant that you were receiving the required voltage and a yellow spark was considered weak or "lazy". This is why I enjoy you guys, you're never to old to learn. Really, thank you

 
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Color of a spark has much to do with contaminants in the ionization path of the spark.