2014 mustang gt idle issues

Asking for a friend with a ‘14 GT. The car is an N/A set up with LT headers, off road x-pipe and dumps. The car has a cobra jet manifold, TB, CAI and tuned on E.

To the issue; car idles rough and turns off at idle almost every time. He says the Spark plugs have about 2k miles on them and doesn’t think it’s tune related (no knock) and no CEL. I’ll try and attach a short vid he sent me. Any input is appreciated.

Could be a vacuum leak. Did issue start after a certain mod or out of nowhere? Has he taken any data Logs?

TVSed GT said:

Could be a vacuum leak. Did issue start after a certain mod or out of nowhere? Has he taken any data Logs?

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Let me ask him. Forgot to mention, he does spray 100/150 shot of nitrous. Issue began out of no where.

I’d start with an idle log at operating temp and select measured afr for both banks. Average value should be 1.0 lambda. If it’s higher then he’s getting unmetered air

TVSed GT said:

I’d start with an idle log at operating temp and select measured afr for both banks. Average value should be 1.0 lambda. If it’s higher then he’s getting unmetered air

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I’ll send this info over to him

Thanks

Were you able to find the issue?


Sent from my iPad using svtperformance.com

Yes and no. It stopped happening, so I have that going for me. It only happened 2-3 times, thought there might be a unmetered air but ruled that out by datalogging. Not sure what to think but fingers crossed it seems to have went away.

I ran into a similar issue and it turned out to be a bad O2 sensor.

Widebands or rear O2?

Front O2's/Widebands. Particularly in my scenario, the drivers side. Only way to figure this out is to watch your STFT's and see if they swing wildly from side to side.