2000 Dodge Stratus: Cylinder 1 misfire


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Old 01-06-08, 11:23 AM
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2000 Dodge Stratus: Cylinder 1 misfire

Out of nowhere, while driving (as reported, not my car) engine starts stumbling at idle. If you keep the RPM up, it smooths out.

Error code P031: Cylinder 1 Misfire

Details;
2.4 DOHC,
Less than 1/8th tank gas,
Temperature has been mid 30s', but now is in the mid 40s',
60k miles,
Plugs changed in the last year (AFAIK),
Orginal cables & coil.

This didn't happen after sitting overnight so I ruled out condensation since it was driven for over 15 minutes when it was noticed. The plug cables are less than 6 inches in length as the coil is right there. I'm wondering about condensation within the gas tank, but if that was the case, why just one cylinder misfiring, why not all?

I didn't check for spark since the 'boots' are overly long with the plug sitting well below and center of the intake manifold.

My thoughts other than condensation from the fuel tank;
1. Bad plug (s),
2. Bad cable(s),
3. Bad coil,
or
4. Bad injector.

Ideas?? Thanks in advance.
 
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Old 01-06-08, 12:07 PM
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And you haven't bothered to pull the plug to look at it? Or to try grounding the #1 wire and plug?

You do make a point that there is difficulty due to the boot, but you have to do something. Not everything comes totally easy.

I have had ceramic insulators crack down inside the plug where I have had idle misfire yet no misfire while driving.
 

Last edited by ecman51; 01-06-08 at 12:11 PM. Reason: added more
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Old 01-06-08, 12:38 PM
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And you haven't bothered to pull the plug to look at it?
I would have to pull the entire manifold off.
Or to try grounding the #1 wire and plug?
and what would that do??
 
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Old 01-06-08, 01:54 PM
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Videobruce: You have to take a better look at your engine. Open the hood, see spark plug wires right on top of the engine's valve cover, pull one out of the valve cover and you'll likely see oil on end shorting out your spark. No manifolds need to be removed; who told you that?
 
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Old 01-06-08, 03:00 PM
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Ok, I took another look and there is no oill in any of the four 'wells'. Except for a very slight amount in the #4 well, all the others are dry except for a very slight 'dried' residue.
 
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Old 01-06-08, 03:10 PM
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Checking to see if you have spark at the wire and plug will help you determine if you have some other issue with either gas or a cylinder problem.

To test the plug wire, take it off the spark plug and put a replacement in the end and hold the metal base of the plug up against bright grounded metal in the engine compartment and see if the plug sparks when the engine is cranked.
 
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Old 01-07-08, 06:13 AM
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Never thought about using a plug to extend the clip burried deep inside that boot................
 
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Old 01-07-08, 11:04 AM
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For one thing, it is nice having an extra plug or two. Then as far as extending the boot as yo say, with the plug-in of the wire way down in the boot, some people stick nails, screwdrivers, etc. down there and then hold all that up against some metal. But with the plug, it snaps good into the wire end and you know then that in there you have good contact. Plus you can more closely analyze what the actual spark looks like from a plug.

Let us know how you make out or if you need more help and others here can jump in to help to.
 
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Old 01-08-08, 03:41 AM
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Replaced the plugs, same thing. Replaced the cables. Bingo!
So far, so good. I didn't figure it was going to be something 'simple'.

Regarding that spark plug 'trick', you would then make contact with the base of the plug to ground and watch for the spark between the gap??
 
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Old 01-08-08, 07:06 AM
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As long as the Ground is against a good clean shiny metal surface, you should see a spark on that plug when the engine is cranked.
When a plug is screwed into the plug socket, that is the normal ground for the plug, so grounding against another metal surface, is an alternate temporary ground...... Laters, Syx.
 
 

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