Replacement Catalytic Converters for a 2003 Ford Mustang with the 3.6L V6 Engine
Published 10/18/2018 >
Products Featured in This Question
Question:
Inlet And Outlet o/2 Sensor Does Part #MF94139 Work For Both Sides On A 2003 Ford Mustang Base Model Just Looking For A Answer, One 0/s Sensor Reads In Flow And Other Reads Out Flow. Duel Exhaust Leading Into One Muffler And Tail Pipe.
asked by: Rollie
Expert Reply:
For starters, let's review the exhaust system on your 2003 Ford Mustang with the 3.6L v6 engine first. From the factory you have a total of four catalytic converters and four oxygen sensors (o2). There are two oxygen sensors directly above the first set of catalytic converters which are called upstream sensors and two oxygen sensors in the middle of the last set of catalytic converters which are called downstream sensors. I have attached a photo of this for you.
The MagnaFlow Stainless Steel Catalytic Converter part # MF94139 is not going to be a good fit for any of the original catalytic converters because the shape is not correct, the inlet diameter of the pipe is not correct, and the sensor location is not in the correct spot if used on the last two catalytic converters.
Instead, you are going to want to use part # MF99174HM for either of the first two catalytic converters or part # MF99355HM for either of the rear two catalytic converters. These converters have the correct shape, inlet/outlet size, and oxygen sensor bungs.

Product Page this Question was Asked From
MagnaFlow Stainless Steel Catalytic Converter w/ O2 Port - Universal
- Catalytic Converters
- Universal Fit
- Federal Emissions
- Any Time Use
- Non-Spun Construction
- Single O2 Port
- No Air Tubes
- Stainless Steel
- MagnaFlow
more information >