[Bglass1223]

(I have a 2014 ford taurus SEL V6)
For about a week now I've noticed my RPMs bouncing up and down, rough idle when parked or stopped at a light, and a shudder or what I'm thinking is a misfire as I'm driving. It happens more when driving at lower speeds, or when I hit the gas and let off. I've also noticed a lack of power when pulling hills and it sounds very "dull" when I'm pulling a hill also. There is no engine light either so I'm not able to have a computer pick up any codes.
I did purchase spark plugs but haven't had a chance to get them changed yet. But I'm just wondering if this sounds like bad plugs or if it could be something else.
Thanks!

 

[kekaye56]

(I have a 2014 ford taurus SEL V6)
For about a week now I've noticed my RPMs bouncing up and down, rough idle when parked or stopped at a light, and a shudder or what I'm thinking is a misfire as I'm driving. It happens more when driving at lower speeds, or when I hit the gas and let off. I've also noticed a lack of power when pulling hills and it sounds very "dull" when I'm pulling a hill also. There is no engine light either so I'm not able to have a computer pick up any codes.
I did purchase spark plugs but haven't had a chance to get them changed yet. But I'm just wondering if this sounds like bad plugs or if it could be something else.
Thanks!

What is your mileage on the vehicle? Are these the factory plugs?

 

[Jeff K]

Have you checked for pending codes? Pending codes will not turn on the CEL until the code becomes a "hard" code.

 

[Bglass1223]

What is your mileage on the vehicle? Are these the factory plugs?

Milage is 94,850
& I'm not sure if they are the original ones or not.

 

[Bglass1223]

Have you checked for pending codes? Pending codes will not turn on the CEL until the code becomes a "hard" code.

No I was told that unless the CEL was on they couldn't run the computer for codes, however I noticed today while driving to work it did finally come on.
I am getting my spark plugs changed tomorrow evening, along with my oil change so I'm hoping that the new spark plugs do the trick & it stops the issues.
It does not do it all the time either, but since this problem has started I usually have a rough idle, and a bad miss while driving especially at slower speeds, or when taking my foot off the gas after driving for awhile.

Sorry, hopefully what I'm describing is making sense I don't know much about it all (which is why I started coming here to check for similar issues)

Thanks for the help I very much appreciate it!

 

[sheila]

Plugs are usually good for ~100k mi. You can get it scanned for codes for free at most auto parts shops.

 

[chartmaker]

No I was told that unless the CEL was on they couldn't run the computer for codes, however I noticed today while driving to work it did finally come on.
I am getting my spark plugs changed tomorrow evening, along with my oil change so I'm hoping that the new spark plugs do the trick & it stops the issues.
It does not do it all the time either, but since this problem has started I usually have a rough idle, and a bad miss while driving especially at slower speeds, or when taking my foot off the gas after driving for awhile.

Sorry, hopefully what I'm describing is making sense I don't know much about it all (which is why I started coming here to check for similar issues)

Thanks for the help I very much appreciate it!

There are codes stored without a CEL light. They are called, "pending codes". My '05 DOHC had obvious misfire with no code. Pending codes showed 3 of Cylinder #3. Replaced that coil and all is good. Plug looked good so no need to replace.
-chart-

 

[kekaye56]

Milage is 94,850
& I'm not sure if they are the original ones or not.

Since you have them already, I would change them and then start troubleshooting from there.

 

[Jeff K]

While not real common, failed or failing COPs (coil on plug) can fail internally. Maybe head to the JY and pick up 1 or 2 COPs and try a new COP on the offending cyllinder. I carry 2 JY spare COPs in the trunk of my 05 SEL Premium Duratec just in case of an on the road failure.

 

[chartmaker]

While not real common, failed or failing COPs (coil on plug) can fail internally. Maybe head to the JY and pick up 1 or 2 COPs and try a new COP on the offending cyllinder. I carry 2 JY spare COPs in the trunk of my 05 SEL Premium Duratec just in case of an on the road failure.

Good call. I got 2 at the JY and replaced the bad one on '05 DOHC. Checked the other by putting JY coil in a front cylinder which is only few minutes change. Then run that one and keep the other in the trunk wrapped and in a zip lock bag. Highly likely never need a spare. Back in the day, got JY distributors for Vulcan, and Essex. Checked and wrapped in cloth and bagged. That keeps failure away. Glad those days are past. Got a JY coilpack on the shelf for my two Bulls that never go too far from home. Finding non cracked coilpack at the JY is nearly impossible now. All in the JY are cracked.
-chart-

 

[Bglass1223]

Found out what the issue was and it's an 02 sensor bank 1 sensor 2, any advice on that?
Thanks so much for all the advice!!

 

[XLR8]

Found out what the issue was and it's an 02 sensor bank 1 sensor 2, any advice on that?
Thanks so much for all the advice!!

Just curious: what led you to this conclusion when you have no CEL and no codes? Have you watched the voltages and waveforms between upstream and downstream sensors (bank 1/sensor 1 and bank 1/sensor 2 -- the sensors before and after the bank 1 catalytic converter)? Also be aware than in many (but not all) cases you'll get indications of a failed downstream sensor when in reality your catalytic converter is the problem, which is why it's important to watch the voltages and waveforms to be certain what the problem really is.

 

[XLR8]

There are codes stored without a CEL light. They are called, "pending codes". My '05 DOHC had obvious misfire with no code. Pending codes showed 3 of Cylinder #3. Replaced that coil and all is good. Plug looked good so no need to replace.
-chart-

chartmaker is 100% correct here. Pending codes can exist for some time before they become active codes and trigger the CEL. I've seen it a lot. I would recommend investing in a scan tool (for your immediate problem and numerous others than may arise in the future). A scan tool is not the same thing as a code reader. A scan tool can do many things a code reader cannot, including reading pending codes. A scan tool can read much deeper into your ECU and other modules, and let you watch what's happening with your car in real time. In this case you can watch your misfire counts in real time on each cylinder. A very good yet inexpensive consumer-grade scan tool is the Actron CP9670.

As a side note here, you can probably get the scan tool a few dollars cheaper and a day or two faster on Amazon, but given Amazon's ties with the CCP and its sustained attacks on free speech, I would recommend using Amazon only as a last resort. As another side note, CarID is a great company -- I've ordered many parts from them, their prices are good, their shipping is fast, and their customer service is great. As a final note, I'm affiliated with neither Actron nor CarID, so I have nothing to gain by you purchasing the scan tool from anyone nor you purchasing anything from CarID (i.e., this is not advertising).

 

[Jeff K]

How did you determine an O2 sensor is bad? Did you get a code? If so, what was the code? If the code was a P0171 and / or P0174, the most likely issue is a vacuum leak or failing PCV valve.

For scan tools and software for Fords (and most Mazdas, as most Mazdas use Ford engines and electronics) I suggest getting Forscan (free download, google it) and a ELM327 OBDII interface for around $25. For a few $ more, you can get one that will show live data is several formatsvfor both the HS CANBUS and MS CANBUS. FOrscan is a VERY powerful diagnostic tool that rivals dealer level scan tools.

 

[Bglass1223]

Just curious: what led you to this conclusion when you have no CEL and no codes? Have you watched the voltages and waveforms between upstream and downstream sensors (bank 1/sensor 1 and bank 1/sensor 2 -- the sensors before and after the bank 1 catalytic converter)? Also be aware than in many (but not all) cases you'll get indications of a failed downstream sensor when in reality your catalytic converter is the problem, which is why it's important to watch the voltages and waveforms to be certain what the problem really is.

Sorry, the CEL did come up a few days ago, I thought I mentioned it but I might have fogot. I did get a code. It was for bank 2 sensor 1

 

[Bglass1223]

How did you determine an O2 sensor is bad? Did you get a code? If so, what was the code? If the code was a P0171 and / or P0174, the most likely issue is a vacuum leak or failing PCV valve.

For scan tools and software for Fords (and most Mazdas, as most Mazdas use Ford engines and electronics) I suggest getting Forscan (free download, google it) and a ELM327 OBDII interface for around $25. For a few $ more, you can get one that will show live data is several formatsvfor both the HS CANBUS and MS CANBUS. FOrscan is a VERY powerful diagnostic tool that rivals dealer level scan tools.

We did end up getting a code pop up for oxygen sensor bank 2 sensor 1 upstream

 

[Jeff K]

What was the code? Most of the time an O2 code DOES NOT mean the sensor itself is bad. The code is telling you that there is a problem with the air/fuel ratio, which is due to vacuum leaks, low fuel pressure, etc, etc.

 

[XLR8]

What was the code? Most of the time an O2 code DOES NOT mean the sensor itself is bad. The code is telling you that there is a problem with the air/fuel ratio, which is due to vacuum leaks, low fuel pressure, etc, etc.

You have to watch the voltages and waveforms on the upstream and downstream sensors, comparing the two, in order to determine the cause of the O2 sensor code. Approximately 65% of the time the ECU is adjusting to an incorrect AFR due to a failed catalytic converter, which you can determine by watching the voltages/waveforms. It's most often a case of the downstream sensor reading being skewed because of a bad converter, and so the ECU adjusts the AFR according to this (skewed) reading, which causes an incorrect AFR in the cylinders (the skewed sensor reading causes incorrect AFR, not the other way around). In this case the ECU will then switch to fallback fueling data tables (AFR/spark/load/trims/RPM/IAT/MAF/etc tables the engineers determined to be relatively safe in open loop, which tables are also used for the first few minutes after the engine is started, and any time the engine is running and not yet up to normal operating temperature). Using a scan tool, one can also monitor ECT and open loop status. When the engine is running and up to operating temperature, but still running open loop, it indicates that the fallback tables are being used.

EDIT: The above applies to a code on a downstream sensor. I mis-read what Bglass said (the code in this case is for the upstream sensor). So, what Jeff K told you is correct.

 

[XLR8]

Just FYI, if you do end up needing to replace the catalytic converter, CarID has good prices, fast shipping, easy returns and great customer service. I've used them a number of times for a number of parts, including a catalytic converter for a 2012 Ford Focus, and one for a 2004 Ford F-150 (which I had to return, and did so with no hassle).

 

[Bglass1223]

What was the code? Most of the time an O2 code DOES NOT mean the sensor itself is bad. The code is telling you that there is a problem with the air/fuel ratio, which is due to vacuum leaks, low fuel pressure, etc, etc.

Yeah I did replace the o2 sensor and it did actually help the miss and the hard idle but I'm still having a shudder "run out of gas" feeling especially when going up hills.
Taking it to a shop tomorrow since it could literally be anything.
No CEL on, and no codes so idk what else to do..