Bad 02 sensor??? please help!
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Bad 02 sensor??? please help!
I have a 97 f150 4.6 xlt with 216000 on it. About 4000 mi. Ago I changed the plugs and wires and noticed coolant on the #4 boot. At the time I didn't have the means to deal with the leak, so just went with the plugs and wires. Ran good for about 2000mi then started running very rough. Got it hooked up to the diagnostic at Orielys and it threw a misfire on #4, and a bad ERG. Changed that plug and ran fine for another 1000 mi. Then same issue. Again changed plug. And got only 300mi. Figured the coolant had ruined the cable so I took the leap and changed the intake manifold gasket (to fix the leak). Put new plugs and wires as well. Now it has a very rough idle. Almost wont stay running without a foot on the gas. And a very sluggish acceleration and no power as well as being very shaky. Now it's throwing a "p1131 and a p0174". I've done alil research and keep coming up with a bad o2 sensor. Not sure where to start. Sorry this is so long just wanted to post,as much info as I could about the issue. Please help! Only vehicle between me and my wife!
Hotshot
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From: St Louis
You do NOT have a bad O2 sensor, it's simply reporting the condition it is detecting.
Most likely, you still have either a fault with the #4 cylinder or you introduced a new vacuum leak when you did all your work on the intake.
Most likely, you still have either a fault with the #4 cylinder or you introduced a new vacuum leak when you did all your work on the intake.
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Ok, it is running worse then be for the gasket change, so would it be safe to assume that the cylinder is ok and that I need to start chasing out a vacuum leak? And if so how do I go about doing that? Just visually inspect boots and lines?
Lead Driver
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Ducon, your not understanding how the system reports issues.
The OX sensor codes are from the sensors that detect the issue, they are not the cause.
The poor idle is from the vacuum leak indicated by the 174 code.
The 174 code is caused by the shift in fuel table due to the vacuum leak.
The coolant in cylinder 4 is likely from a heater hose leak right over the top of the #4 cylinder.
Bottom line is the codes do not tell you what to replace.
Replacing the plug several times is not addressing the cause of the misfire in that cylinder. That should be the hint.
Good luck.
The OX sensor codes are from the sensors that detect the issue, they are not the cause.
The poor idle is from the vacuum leak indicated by the 174 code.
The 174 code is caused by the shift in fuel table due to the vacuum leak.
The coolant in cylinder 4 is likely from a heater hose leak right over the top of the #4 cylinder.
Bottom line is the codes do not tell you what to replace.
Replacing the plug several times is not addressing the cause of the misfire in that cylinder. That should be the hint.
Good luck.
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I have fixed the coolant leak in the #4 cylinder it's not the heater hose above, I too came to that conclusion for the leak. But it was the intake for sure.
also there is no longer a misfire on any cylinder. The vacuum leak seems to fit the symptoms where do I start addressing that?
also there is no longer a misfire on any cylinder. The vacuum leak seems to fit the symptoms where do I start addressing that?
Lead Driver
Joined: Sep 2006
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The code is almost always a vacuum leak.
If for one bank only, there is a leak at one of the ports in bank 2 intake.
A check with a Scanner looking at both long term fuel trim tables will tell if it's one or both banks shifted to any degree.
A Scanner looking at the short trim table for bank 2 will react instantly to any intake through the leak with a flammable spray.
A non flammable spray will not react.
Good luck.
If for one bank only, there is a leak at one of the ports in bank 2 intake.
A check with a Scanner looking at both long term fuel trim tables will tell if it's one or both banks shifted to any degree.
A Scanner looking at the short trim table for bank 2 will react instantly to any intake through the leak with a flammable spray.
A non flammable spray will not react.
Good luck.
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