My engine is misfiring can you fix it?

Tiny
GTWOOD
  • MEMBER
  • 1998 HONDA CIVIC
  • 336,000 MILES
I have a 1998 Civic Ex 1.6 VTEC, with 336,000 miles! It runs great. But. When it idles it gets the flashing check engine light. My mechanic checked the compression and found #3 cyl at 70 lbs. He suggested that I run sea foam through the sys. As problem may be caused by carbon build up. I did that, but still get the "flashing light". The engine runs smooth, even at idle, the valves don't make any noise. Could there be another factor causing the problem? Mechanic is loathe to do a valve job as the added pressure from new head gasket will cause the engine to "smoke". It's a sweet running car!
Thanks
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Saturday, November 16th, 2013 AT 7:46 AM

30 Replies

Tiny
HONDATECH1983
  • MECHANIC
  • 109 POSTS
Have you had the valve clearances checked? If the compression is low on a cylinder 1 reason could be the valve clearances may be keeping a valve(s) open a little. I would definitely want to make sure of that before I decided to do any major work. Also, with 70 psi I would think you'd have a mis-fire under any condition (idle, cruising, etc.). I'm assuming since the engine light is flashing it is probably a noticeable rough idle? I would think with that low of compression you would notice it a higher RPM's as well. I would have the valve clearances checked if they haven't already. Get back with me after you do so
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Saturday, November 16th, 2013 AT 8:26 PM
Tiny
PMP
  • MEMBER
  • 177 POSTS
  • 1998 HONDA CIVIC
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 151,000 MILES
Hello, Yesterday my check engine light went on. Then today it went off. So I decided to check the codes. I got p0300, p0301, p0304. Ngk iridium plugs and ngk wires installed a few months ago. Dizzy is about a year old. Any suggestions? Also im getting hard starts and rough idles on cold starts like he last few days in a row. It was idling like it was on 3 cylinders.
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
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Do you have coolant losses and/or overheating issues?

Those are misfiring codes and it could be spark plugs, plug wires, distributor rotor or fuel pressure or injectors. This can can help fix it

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down this guide and report back.
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
PMP
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Last night and today the guage was going up a little not more then 3 quarters. Then when I hold my foot no the gas like at 4k rpm it goes down. My resivor is going empty like every 2-3 weeks.
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
Most likely you have compression leak with one or more cylinders. Get a compression test done with a cold engine.
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
PMP
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And what would that mean if it had a compression leak. Is it hard to do a compression test if I rent it from auto zone
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
KHLOW2008
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That wuld mean a bad head gasket which would result in coolant looses and the misfiring.
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
TONYPRZY
  • MEMBER
  • 2 POSTS
  • 1998 HONDA CIVIC
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 134,000 MILES
Thanks for taking the question. My problem started all of a sudden when the car started studdering while it was idleing. I drove it home from work, and on the highway the engine started misfiring once I got to about 50 mph. I think misfiring is the right term: it hesitated and the car jerked every once and a while. I replaced the spark plugs and the cables, and now the car runs smoothly on the highway; however, the car still shakes a lot while it is idleing and the check engine light is still flashing. I listened under the hood, and I can hear a "clacka, clacka, clacka" sound intermitantly coming from inside the engine, and the engine seems to be shaking a lot. Usually, the sound comes in sets of three like in the quote. I would appreciate any help. Thanks
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
F4I_GUY
  • MECHANIC
  • 3,302 POSTS
Do a compression test. You may have a bent valve or something of that nature.

If the engine is mis-firing, you have to figure out why it's mis-firing. Try doing a cylinder balance test to see if you can isolate a cylinder.
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
POD12701
  • MEMBER
  • 1 POST
  • 1998 HONDA CIVIC
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 230,000 MILES
I have a 98 civic lx little 4 banger 1.6L I have a misfire on cylander one according to the computer. I do my own mechanical work this is the only car that has ever had me stumped. Check engine light is on for a misfire on cylander 1 but number 1 isnt misfireing number 2 is I pull one the engine dies down and really misfires I pull plug number 2 and I have no diference. I plug the computer in it says its the ignition module and the misfire on cylander one. I did a brand new cap rotor wires plugs. I even adjusted the valves cause I have spark on all the cylanders I know its getting gas I can smell it in the cylander I even checked the timing. Im outta ideas and I live in ny so I cant put the car on the road with the check engine light on help me please someone
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
PEAR69
  • MECHANIC
  • 1,482 POSTS
 Is the engine running rough all the time like the cylinder is missing "all the time"? A misfiring cylinder doesn't have to be misfiring all the time, it can misfire intermittently. An ignition module will do that. However, have it tested before replacing--they are expensive for your car.  If you are sure you have spark, and have tested to be sure, then it is almost impossible to just smell to see if there is fuel getting into the cylinder. The only true way to tell if there is fuel getting into the cylinder is to take the spark plug wire off the plug and run the engine for a minute or two. Then stop the engine and quickly take out the spark plug. It should be soaked (wet) from fuel. If not soaked, but a little wet, it could be a blocked or failing injector.  Let us know what you find.
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Monday, January 4th, 2021 AT 12:48 PM (Merged)
Tiny
WOODY4SPENCE
  • MEMBER
  • 1 POST
  • 1998 HONDA CIVIC
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 144,980 MILES
It was misfiring and hesitating, so I replaced the plugs and wires, disconnected the batter to reset the computer, and it ran great! Two days later, its having a hard time starting and the check engine light is on again for cylinder mis-fire and now its starting to attempt to over heat, and about a week ago it blew a radiator hose, so that got replaced as well as the thermostat was not working correctly. Any suggestions on what to do next? Auto Zone said to redo the sparks plugs, I am thinking of the rotor and distributor, but I don't see how that is applying to it not starting well.
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Monday, January 4th, 2021 AT 12:49 PM (Merged)
Tiny
F4I_GUY
  • MECHANIC
  • 3,302 POSTS
Do a cylinder balance test. Whichever cylinder is 'dead' you should test for fuel and spark to that cylinder. If they are both present, then you need to do a compression test.

However, when you do a tune-up you should always replace the ignition cap and rotor as well. Make sure you are using NGK spark plugs as well.
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Monday, January 4th, 2021 AT 12:49 PM (Merged)
Tiny
HONDACIVIC1998
  • MEMBER
  • 3 POSTS
  • 1998 HONDA CIVIC
Electrical problem
1998 Honda Civic Manual

The car missfires sometimes, white/grey smoke comes out the exhaust. When I remove the 4th spark plug wire (nearer to the battery side) and put it in it seems fine, when I take out the TPS no smoke or misfire happens, when I put it back in it continues to giveout smoke and misfore.

I have replaced spark plugs but not wire. Bleeded the coolant and replaced. The car has been out of commision for nearly 3 years. A tiny amount of petrol was left in the car. Oil and filter has been changed.

I would appreciate if you or anyone can help as I spent alot already on this car, more and more problems keep appearing.
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Monday, January 4th, 2021 AT 12:49 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
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Hi HONDACIVIC1998,

Do a compression test of the cylinders to see if there is any problem
A bad cylinder would cause the misfiring described.
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Monday, January 4th, 2021 AT 12:49 PM (Merged)
Tiny
HONDACIVIC1998
  • MEMBER
  • 3 POSTS
Hello KHLow2008, Thanks for the reply,

Even if I take out the TPS sensor will it indicate cylinder problems when Compression test is done? When TPS is out there is no smoke or misfire(small missfires every minute or so)

I took it to MOT today, it passed everything except emissions, now I dont know if it is the sensor which regulates pertrol or catalyic converter or something else like the distributor.

Does this type of car have oxygen sensors?

In the meantime I will take it tommorrow down a motorway and chuck Redex in to see if it helps.

Bear in mind the car has not been drivin in 3 years and had no previous probs.
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Monday, January 4th, 2021 AT 12:49 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
Sitting for so long can cause things to freeze up and all sorts of problems.

What was the reason for emission failure? Any DTC?
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Monday, January 4th, 2021 AT 12:49 PM (Merged)
Tiny
HONDACIVIC1998
  • MEMBER
  • 3 POSTS
Ok I have got it checked out for cylinders and gasket for leakes ect, no probs. So then I changed the throttle body and made a huge improvement on the acceleration and petrol consumption.

The misfiring stopped, very high idle revs came down from 2500 to abt 1500.

Emission failed because of the rich intake of petrol which produces 10 times its normal emmission.

As it stand now, no white smoke, catalyic converter looks okay, cylinders ok, throttle body ok. However still idles high at 1500 revs, it also fluctuates between 1000-2000 revs when its idle or on neutral. As well as petrol consumption. Half tank already gone did only 55 miles and itls only a 1.4i.

If its not mechanical no more could it be electrica?
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Monday, January 4th, 2021 AT 12:49 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
It could still be mechanical. There could be a vacumn leakage. If the throttle body is a used unit, the valve could still be stuck in an open position thus the high rpm.

Try unplugging the IAC connector and reconnecting, noting the rpm change. If none, the IAC could be stuck. Used throttle body sometimes gets stuck.

Remove air iintake hose and cover the lower port, if idlie comes down, the IAC is opening too much.
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Monday, January 4th, 2021 AT 12:49 PM (Merged)
Tiny
TSA
  • MEMBER
  • 2 POSTS
  • 1998 HONDA CIVIC
Honda Civic EX 1998, 132,800 miles, 4-cylinder, automatic, frontwheel drive; I am the original owner, living in Arizona, current temps hovering over 100 degrees (Aug-Sept), car tuned up a month ago. For a few weeks, from a cold start going to work in the morning, the car would hesitate intermittently for a few seconds, with the motor running like it was going over waves on a lake. Too early to call my mechanic and it would smooth out after a block anyway, after which time I would promptly forget about it †til the next morning when it did it again. Finally, it did it on the way home from work, only worse, as †still before 5pm, called mechanic, 'brought it in next morning. He changed out the cap and rodder, thinking bad parts from the tune-up; car runs fine on the way home. Next morning, problem returned. On my way the check engine light comes on (first time) and continues flashing. Flashing... Flashing... Brought it in, my mechanic changed the ignition coil, car runs fine. Next morning, the hesitation is back. On my way home from work, the check engine light comes on solid (not flashing). Drive straight to mechanic; he scans. On the generic scanner: codes P0302 and P1399. On his buddy’s scanner: codes P0300, P0301, P0302, P0303, P0304 misfires, “OK to Drive.” He’s not sure what to do next. I need the vehicle so I go with “OK to drive” and leave, but the check engine light is still on and the car is doing the morning hesitation thing. I’m keeping it under 4000RPM. Per my mechanic’s suggestion, until I can do without the car long enough for someone to figure it out what’s the fix... Can you help?
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Monday, January 4th, 2021 AT 12:49 PM (Merged)

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