fordguy427

I have a 07 Mustang GT , bought new, it just turned 5000 miles. This spring I put Pypes "high flow" cats with an X-pipe with their mufflers. I maybe put 800 miles on it since the install. On a cruise over the weekend, the engine light came on. Went home and put the reader to work and came up with this code...P0430...Catalyst Efficiency Below Threshold[bank 2]
Can this be because of the "high flow" cats or did one of them take a dump?? I have no trouble with driveability or idiling, etc.
Thanks,
Lee

pascal

Wrong section son...
Let me send you where you'll get the right answers.

cliffyk

It could possibly be because of "hi-flow" cats (there's really no such thing, they are just smaller than the stock cats; meaning less ceramic substrate, meaning very slightly less restriction--generally not enough to matter.

That aside, I would first suspect the rear O2 sensor on bank 2...

jo3phresh

i have a similar issue, same code. but my car has a rougher idle and is getting horrible gas milage at idle. it has a O/R xpipe but it didnt pull a code when i installed it. under the p0430 it says a large vacuum leak could be responsible as well. but i cant find it? any clues

tx_zstang

Do a search for P0420 and P0430. You'll get your answers.
Most often it's due to high-flow cats or no cats. It wont affect drivability; other issues would cause that.

madmann26

Get 4 sparkplug non-foulers. They are 18mm in size I believe.

Drill out 2 of them. Be careful to NOT damage the threads.

You have 2 left. These should have little holes in the bottom of them.

Screw the one you just drilled out into it. Then screw the o2 sensor into that one.

In short, you want to make sure that the non-fouler that has the small hole in the end, is the end that you screw into your exhaust.

I had the same issue, couldn't pass emissions because of my high-flow cats because of the CE light.

mysticcobra1996oregon

i just installed non foulers, still throwing p0430. could bad front o2 be messing this up?

cliffyk

No, P0430 indicates that the catalyst efficiency monitor feels the cats have failed--click here for more--it is unrelated to the front sensors in any way, unless accompanied by some other DTC that does reference the front sensors.

Did you reset the code with a scan tool, or disconnected the battery for 10-15 minutes after installing the non-foulers (which BTW in my experience have a less than 50/50 success rate)?

You can make your own MIL eliminators for $6 or so...

mysticcobra1996oregon

I already have went through about 4 pairs of the mil eliminaters from american muscle. I did reset with obd2 and unpluged battery overnight. I think wire harness could have been damaged when new exhaust was put on.

cliffyk

Then that would have to be repaired before worrying about anything else...