Need advice. Problem with car?, Tune?

[Youngmustang]

So this was my original problem my car was idling really weird like it wanted to turn off but then the revs would go back up. The check engine light was on and the Code "P2251 02 sensor Negative Current Control circuit/open", 2 other codes P0030 "H02S Heater Control Circuit" and P068A "ECM/PCM Power Relay De Energized Performance- Too early". I do have a tune, headers and CAI. . I had the tune, headers, and CAI for over a month with no problems. At first I thought it was the tune but somebody recommended to replace the faulty 02 sensor. So I did replace the 02 and the codes never appeared again. But now I have the same problem with revs going up and down but now I have a P0308 code "Cylinder 8 Misfire".I can't drive the car like this because is surges and shakes. I really don't want to take it to the dealership because of the Mods I have. I was hoping it was the tune because thats an easy fix but at this point I don't think it is. Any Advice?
[ame]

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[B0SS603]

If you don't want the dealer to look at it, which is understandable as they may void your warranty, have a good local shop take a look. You may have to pay a few bucks to have it diagnosed. Otherwise just remove the tune and mods and take it to Ford.

 

[2015 Silver GT]

Are you using o2 extensions?

 

[Youngmustang]

Are you using o2 extensions?

No 02 extension. I didn't need them they fitted fine.

 

[craigsix]

i had that problem with my intune. it needed updated to the latest firmware.

 

[madsedan]

You talk to your tuner about it yet? IF it was running fine before and no changes for a month before this new issue than its not the tune but something the tune is doing may have caused a problem with a sensor.

 

[Youngmustang]

You talk to your tuner about it yet? IF it was running fine before and no changes for a month before this new issue than its not the tune but something the tune is doing may have caused a problem with a sensor.

That's what I thought. Maybe something off with the tune that caused the problem. But as of right now it seems like it's a mechanical problem. So I need to figure this out before I ask for another tune. It's tuned through LUND BTW. I replaced the passenger front o2 sensor and that got rid of the original codes.But I still have the same problem with the rough idle and surging and the new code with cylinder 8. Could the bad O2 sensor cause the problem with cylinder 8? I just hope it's not too serious because I'm screwed now that I have tuned it.

 

[2015 Silver GT]

Who's longtubes are you running? o2 placement in the collectors are an issue on the 2011-2014 cars and I expect it to rear it's ugly head on these cars soon.

 

[madsedan]

I seriously doubt its anything to do with the tune. I would check any hardware items you changed first. If you installed an intake, exhaust, headers, etc. make sure they are installed correctly and any/all sensors related to them are installed right as well, no intake or exhaust leaks found.

The sensors are very simple devices, regardless of the type, and they either work or they don't. They would not be effected by anything with the tune unless the tune is causing what they read to be way out of whack or the tune is sending to much current to the sensor.
I'm not a Mustang guy before the one I own now so I'm not up to speed on previous model year issues like another poster mentioned in regards to the headers. But if the sensor you are having problems with is one attached to the headers I'd contact them to see if they have advice. Unless you had a bad sensor or caused physical damage during the header install your factory O2 sensor should be good for a couple years, lots of miles.

 

[Need4Speed15]

Pull the #8 plug and take a look at it, hopefully its not oil fouled. Is the car smoking at all out the tailpipes?

 

[Redeemer]

Also where did you purchase the replacement O2 sensor. Long ago and far away I worked at Autozone, and Advance, and over half of the Bosch O2 sensors we sold came back, bad out of the box. Quality control was pretty terrible.

 

[madweazl]

I would start by talking to Lund; this may be something they have seen before and save you some headaches. Cam lope tune by chance?

 

[Asharus]

sucks man. this is the main reason why i havent modded my car yet. i hate it when this happens. good luck.

 

[Youngmustang]

Who's longtubes are you running? o2 placement in the collectors are an issue on the 2011-2014 cars and I expect it to rear it's ugly head on these cars soon.

Stainless works catless

I would start by talking to Lund; this may be something they have seen before and save you some headaches. Cam lope tune by chance?

No lope tune. I did ask them about the o2 sensor codes and they said it was a mechanical issue. So that's when I replaced the o2 sensor. I haven't asked about the cylinder 8 misfire though. I will ask and report back.

 

[craigsix]

have you tried running the stock tune just to see? diablo had me run stock tune and disconnect battery cables and touch the negative and positive cables together for 10 seconds.

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