# Misfire Cylinder No 4



## PWJ (Sep 26, 2007)

I have a 98 Nissan Frontier with 2.4L engine. I recently had a used engine installed. Engine had about 12K miles on it. Since I had it installed, I keep coming up with a misfire on cylinder 4. I have had intake ports cleaned, new plugs and wires, new EGR valve but the misfire keeps coming back. It's been about 2K miles since the last work was done on it and the misfire has returned. Any thoughts on what is causing this and what may be done to fix it?


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## azrocketman (Oct 5, 2005)

PWJ said:


> I have a 98 Nissan Frontier with 2.4L engine. I recently had a used engine installed. Engine had about 12K miles on it. Since I had it installed, I keep coming up with a misfire on cylinder 4. I have had intake ports cleaned, new plugs and wires, new EGR valve but the misfire keeps coming back. It's been about 2K miles since the last work was done on it and the misfire has returned. Any thoughts on what is causing this and what may be done to fix it?


1) Is the misfire a miss or is it occasional? Can you feel the misfire (e.g. hesitation or roughness)? If so, can you feel it at all times, while the engine is hot or cold, or only at certain engine or vehicle speeds? 

2) Do you know it's on cylinder 4 because of troubleshooting or because the check engine light is on and you're getting a P0304 code? Does the check engine light ever flash during vehicle operation?

3) When you say you've had the intake ports cleaned are you referring to the EGR ports in the intake manifold or are you referring to cleaning the fuel injectors?

4) Have you inspected or replaced the distributor cap?

5) Is the engine a rebuild with only 12k miles on it or a low mileage engine from a wreck? Was the engine complete or did you install accessories, e.g. intake and exhaust manifolds, fuel rail and injectors, from the old engine? How many miles on the old engine if you removed parts from it?

You might want to look at this thread: "Stumble between 1500 and 2000 rpm". I had a similar symptom about 2 years ago.

Steve


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## PWJ (Sep 26, 2007)

1. Miss is constant though most notable 3rd through 5th gear.

2. I am getting a code with the engine check lights on. I also pulled the number 4 plug wire during idle and that did not affect the way it was idling roughly. The check engine light comes on without blinking but as you rev engine it begins to flash.

3. I believe both the injectors and ports were cleaned.

4. The distributor cap was inspected the last time I had the problem (when I had the ports and injectors cleaned) and the mechanic said it was good to go. Have not looked at it this tme.

5. The engine was a low mileage engine from a wreck. It came with basically just the block. The accessories came from the original engine which had abotu 170k on it.


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## azrocketman (Oct 5, 2005)

PWJ said:


> 1. Miss is constant though most notable 3rd through 5th gear.
> 
> 2. I am getting a code with the engine check lights on. I also pulled the number 4 plug wire during idle and that did not affect the way it was idling roughly. The check engine light comes on without blinking but as you rev engine it begins to flash.
> 
> ...


You need to verify that the EGR ports in the intake manifold were cleaned. This is not a chemical flushing rather, it requires removal of the four hex plugs from the top of the intake manifold and scraping carbon from the ports (approximately .25 inch diameter). There is a Nissan technical service bulletin that describes the maintenance (it is referenced in the previously mentioned thread). If the EGR ports were not cleaned that would be my first item to check. I'd also check the EGR tube that goes from the manifold to the EGR valve as these can also clog.

The check engine light flashing indicates a severe misfire. Can you use a mechanics stethoscope and verify that the number 4 fuel injector is cycling? I might pull the number 4 injector and swap it with another cylinder. If the problem follows the injector, you have your answer.

Have you run a compression check on the engine? It's possible you have a blown head gasket or some other cylinder specific engine problem. When you say the replacement engine was basically just a block does that mean there was no head? If the head was from your 170k engine was the head serviced (e.g. valve grind)?

Steve


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## PWJ (Sep 26, 2007)

Following is a list of what I have had done to the engine since it was installed:
New EGR Valvalw and gasket
Valve Shims on Cylinder 4


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## PWJ (Sep 26, 2007)

The EGR Ports were cleaned and the head from my old engine was used and was serviced prior to installation. Last check of compression (don't remember what it was) but mechanic stated it was good and what compression should be for a 12k engine.

I don;t have or know how to use a mechanic's stehoscope.

May be of interest. This most recent episoe occurred soon afetr I gassed up at Racetrac. I used 89 octane. Got on the interstate cruising at 75-80 and the engine started hesitating. Hesitation turned to spitting, sputtering, and knocking though the engine never did die. Check engine light went off. I got off the Interstate think that perhaps I got some defective gasoline. I got a bottle of Seafoam (a gasoline additive) after a few minutes the engine ran about 80% better than before which kind of confirmed to me that maybe it was bad gas.

Is this a possibilty?


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## azrocketman (Oct 5, 2005)

Bad gas is a possibility but I'd be surprised that it would manifest itself as a cylinder 4 misfire. It does raise the question: Have you changed your fuel filter recently (within the last 10k miles)?

You use a mechanics stethoscope just like a doctor uses his. You can try to use a piece of tubing against the part in question as a cheap substitute.

Steve


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## PWJ (Sep 26, 2007)

Fuel filter was changed about 5k ago. In light of possible bad gas would you reccommend changing it out. Would seem like I would be getting a code on all cylinders. I used and piece of clothes hanger and could hear a faint cliking in all injectors. Is that what I am looking for?


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## PWJ (Sep 26, 2007)

Also, Assuming the mechanic did a good job of cleaning the EGR ports adequately, is there any condition that would cause the ports to clog up this soon? Is it possible that crappy gas could cause them to clog up being that it does not combust properly? I know I am probably asking a lot of stupid questions (not a mechanic) but I am pretty deep in the pockets with this engine and am grasping at anything possible. Paul.


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## azrocketman (Oct 5, 2005)

Paul,

1) It's possible a real bad tank of gas could damage a new filter. If that is the case I'd be worried about the fuel pump and tank pick-up screen. In any case, I agree withg you that a filter problem would show up as a cylinder 4 problem only.

2) Using the coat hanger as you described is like a stethoscope. You should hear the clicking of the operating injectors.

3) I do not think that bad gas could cause the EGR ports to clog within 10 or 15 thousand miles.

At this point I'd say the most likely culprits are a compression (or valve) problem on number 4 cylinder or an injector problem. I'd do the compression check first. I'd follow that up by swapping the #4 injector with another cylinder. I'd also replace the distributor cap and rotor on basic principle (and they are not that expensive).

Steve


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## PWJ (Sep 26, 2007)

So, all things considered, any recommendations?


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## azrocketman (Oct 5, 2005)

Replace distributor cap (mostly on principle), compression check, replace number 4 injector or troubleshoot by swapping injector with another cylinder.

Steve


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## PWJ (Sep 26, 2007)

Thanks, Steve.!


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## PWJ (Sep 26, 2007)

Brought it in to a GOOD mechanic. He found that a small piece of the plug on Cyl 4 had broken off and was down in the cylinder. Now it runs like a 12k engine is supposed to. Thanks for all your help and suggestions.


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## azrocketman (Oct 5, 2005)

Good to hear you found the problem and that you closed the loop by telling the forum what you found. Could you tell if the plug was damaged before or during installation or if it was just a bad plug?

Steve


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## dwest1023 (Apr 6, 2007)

PWJ said:


> So, all things considered, any recommendations?


I am surprised that not one person has mention the ignition coil. I understand this is a big problem with Nissan


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