5.4 miss
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5.4 miss
Read all the posts on 5.4 miss and it has helped me tremendously with changing the plugs on the 5.4
I have a problem still... The computer still shows miss fire on nr. 4 and now nr. 3 and also a lean indication from the o2 sensor... can this all be from a cop bad. I had it originally scanned at autozone and they said the nr4 was misfiring , but i believe they did not scan the whole thing, just the first one.
The vehicle is a 98 expiditon with 5.4 and 4x4. it has 85,000 miles on it. the plugs all looked good but nr 3 and nr 4 which were fouled out, no oil on them , just fouled. the others were good, just worn out. they looked like the original plugs.
any help is appreciated. thanks in advance.
Rick
I have a problem still... The computer still shows miss fire on nr. 4 and now nr. 3 and also a lean indication from the o2 sensor... can this all be from a cop bad. I had it originally scanned at autozone and they said the nr4 was misfiring , but i believe they did not scan the whole thing, just the first one.
The vehicle is a 98 expiditon with 5.4 and 4x4. it has 85,000 miles on it. the plugs all looked good but nr 3 and nr 4 which were fouled out, no oil on them , just fouled. the others were good, just worn out. they looked like the original plugs.
any help is appreciated. thanks in advance.
Rick
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I'm a little confused, have you changed all the plugs and/or the COP's? Also, by fouled what exactly do you mean? Fouled is usually to much fuel, carbon, or oil on the electrodes. Finally regarding the O2 sensor, are you getting a CEL and code? If yes, which sensor?
I've seen a number of posts here concerning missing on the 3-4 cylinders. From what I remember it is usually from water sitting on the plug. Some one else out there could probably give you the details as to where the water originates from but does it appear you've had water on the 3 and 4 plugs?
I've seen a number of posts here concerning missing on the 3-4 cylinders. From what I remember it is usually from water sitting on the plug. Some one else out there could probably give you the details as to where the water originates from but does it appear you've had water on the 3 and 4 plugs?
Cargo Master
Joined: Dec 2004
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From: NE Texas
Getting an indication of a lean condition does not mean that the O2 sensor is bad. In that case the O2 sensor is the messenger.
I would assume that it is telling you the truth and start troubleshooting a lean codition. To start with check the fuel pressure. When was the fuel filter changed last?
Good luck,
Doc
I would assume that it is telling you the truth and start troubleshooting a lean codition. To start with check the fuel pressure. When was the fuel filter changed last?
Good luck,
Doc
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5.4 miss
yes I changed the plugs, not the cops. The plugs were black on nr 3 and 4 but were a greyish on the other 6 plugs. the lean indication was the nr. 1 bank and the first o2 sensor. I assume this is due to the 3 and 4 cops not firing. I checked the cop when pulled out, but found not a drop of condensation on the cop or near either cop...
My question is if the nr 3 and nr 4 cop misfiring would this give the 02 sensor a lean indication?
Thanks in advance
Rick
My question is if the nr 3 and nr 4 cop misfiring would this give the 02 sensor a lean indication?
Thanks in advance
Rick
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Joined: Dec 2005
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Just off the top of my head, I would think you would get a rich mix if 2 cylinders are not firing all the time (fuel not burning) but with the new computer systems making adjustments you never know. Regardless, I'd change the #3 and #4 cops. Worry about the lean issue once you get rid of the miss.
BTW: I'm a little clueless sometimes, but I've thought and thought and can't figure out what nr (re: cylinders) means. Clue me in.
BTW: I'm a little clueless sometimes, but I've thought and thought and can't figure out what nr (re: cylinders) means. Clue me in.
Cargo Master
Joined: Dec 2004
Posts: 2,232
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From: NE Texas
I think that nr. means number and he is referring to the right bank.
I agree with Grsyhands, you need to fix the miss first. What might be less expensive would be to swap the COPs from three and four with the COPs from two other cylinders and see if the miss follows the COPs.
Good luck,
I agree with Grsyhands, you need to fix the miss first. What might be less expensive would be to swap the COPs from three and four with the COPs from two other cylinders and see if the miss follows the COPs.
Good luck,
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Thanks for the information on the 5.4 miss. It turned out to be the cop on number 3 and number 4 sparkplug.
Runs like a top now with no engine light on. gas mileage and performance has returned.
Thanks again.
Rick
Runs like a top now with no engine light on. gas mileage and performance has returned.
Thanks again.
Rick
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