Lean bank 1 DTC code if exhaust gasket leaking?

[dwcopple]

Pretty sure my passenger side exhaust gasket from manifold to downpipe is toast. Driving today I got p0135 and a 2nd DTC for lean bank 1. Would that gasket cause that or is my o2 sensor toast?

 

[07GtS197]

Could be but since there’s a code for the heater circuit I’d suspect it’s the sensor itself. It’s still a good idea to get under it and check the gasket anyway. I’ve had an issue where the manifold studs backed out partially so the x pipe couldn’t be torqued down all the way causing issues but I don’t think it threw any codes. It would clank around and you could see some smoke after revving.

 

[That Mustang Guy]

Depending on how bad the leak is will dictate how off the STFT will be.
Code P0135 occurs when the powertrain control module tests the upstream heated oxygen sensor's heater circuit on Bank 1 and detects a short in the circuit or excessive resistance in the heater circuit.

 

[dwcopple]

Exhaust sounds slappy on passenger side until the metal heats and expands closing any gap.

 

[That Mustang Guy]

If it sounds like that at the cold start it needs to be fixed along with the o2 sensor. Over time it's going to get worse obviously. Your gas mileage will keep going downhill. Always change O2s in pairs. The only O2 I suggest is one from the dealer or an NTK O2. The reason for an NTK is because they make the OEM factory O2s for Ford. I'll post a pic later, but if you look at a factory O2 it is embossed with NTK and if you look at the NTK O2 from Advance Auto it also says oe mfr: NTK.

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[dwcopple]

If it sounds like that at the cold start it needs to be fixed along with the o2 sensor. Over time it's going to get worse obviously. Your gas mileage will keep going downhill. Always change O2s in pairs. The only O2 I suggest is one from the dealer or an NTK O2. The reason for an NTK is because they make the OEM factory O2s for Ford. I'll post a pic later, but if you look at a factory O2 it is embossed with NTK and if you look at the NTK O2 from Advance Auto it also says oe mfr: NTK.

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Thanks. I'll order 2 NTK sensors. I already have a new oem flange gasket ready to install too. I'll probably toss some copper rtv up there as well.

 

[That Mustang Guy]

Yeah, I always put a high temp RTV on both sides of the gasket. Just a nice little layer, not a glob LMAO. I have part numbers if you need them?

 

[dwcopple]

Sure!

 

[That Mustang Guy]

Give me just a bit and I will get them for you.