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Misfire Code Cyl 4

blue-ss-camaro

By blue-ss-camaro
in Ask A GM Technician

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blue-ss-camaro Enthusiast

blue-ss-camaro

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I keep getting a code of misfire in cyl 4. It is only in the morning when it has been really cold out like 35. And it will only happen about mile down the road when i am going to work. do it for about 20 seconds and then clear up. When it does it the check engine light flashses like crazy. I have replaced the plugs and I Will be replaceing the wires, cap and rotor. Just trying to get other ideas if that doesnt work. oh and i put a can of seafoam in the gas. thaks in advance

blue-ss-camaro Enthusiast

blue-ss-camaro

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I keep getting a code of misfire in cyl 4. It is only in the morning when it has been really cold out like 35. And it will only happen about mile down the road when i am going to work. do it for about 20 seconds and then clear up. When it does it the check engine light flashses like crazy. I have replaced the plugs and I Will be replaceing the wires, cap and rotor. Just trying to get other ideas if that doesnt work. oh and i put a can of seafoam in the gas. thaks in advance

 

the truck in a 98 gmc k 1500 4wd with a 5.7

blue-ss-camaro Enthusiast

blue-ss-camaro

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Ok I hve replaced the plug wire and cap and rotor. truck still does the same thing except just not as bad. Whne I took the cap off there was a bunch of oil or grease under it and all over the rotor. I was told that the injectors can cause this. does anyone know????

bobcat5544 Enthusiast

bobcat5544

Posted
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First off the distributor should never have oil and grease in it. That would cause a missfire.

 

and the fuel injectors would not cause the oil and grease to get into the distributor

frupp Enthusiast

frupp

Posted
Posted

My truck had a misfire code for one cylinder, too. I replaced plugs and wires with no effect. So I decided to do a compression check to see if I had a bad cylinder. When I cranked the engine with all the plugs out, raw gas shot out of cylinder #3.

 

It turned out I had a bad injector that was sticking open. I decided to check the oil level and found it had gone up, indicating gas draining into the crankcase. I was lucky I didn't get a hydraulic lock in that cylinder.

 

I replaced that injector and checked the others on that side of the engine while the fuel rail was off, and the engine now runs perfectly. After an oil and filter change (immediately), the check engine light is off (it flashed like yours did).

 

Frank

blue-ss-camaro Enthusiast

blue-ss-camaro

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First off the distributor should never have oil and grease in it. That would cause a missfire.

 

and the fuel injectors would not cause the oil and grease to get into the distributor

 

I know the fuel injectors would not cause oil or grease in the distibutor and I also know that there should not be oil or grease in the distributor. I just was saying that cause I thouhgt the cap and rotor was the problem and it is not. I think I am going to try the injector in the cylinder. I am open to other suggestions also. I amost forgot the truck dos it at all times of the day now. not just in the morning. I hope its just the injector.

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