PonyBoy06

This may end up being a long winded post, but I'm going to try to keep it as succinct as possible. To start with, here's some specs, to save you from asking. If you need more info, just ask. I can't guarantee I'll know the answer though

4.6, manual transmission
K&N CAI
Magnaflow exhaust, x pipe, dual cat
Likely tuned, but I'm not sure

I recently purchased a 2006 GT as is from a dealer. When I initially bought it I was told they were waiting on a part for an o2 sensor issue that was setting off the check engine light (rookie mistake, I know, buying it while it was still an issue). They beat around the bush for months, and eventually did some work on the mass air flow sensor, but warned me that because of the extensive exhaust upgrades, it would probably come back on. And it has.

Codes:
P0430: Catalytic Converter below threshold (Bank 2)
P2195: Undefined code (I'm told only the dealer can read this?)

Symptoms:
Rough idle about a minute or two after start up. Very inconsistent. Sometimes it lasts a minute or two and sounds like it's going to stall, other times it may only last 30 seconds. If I start to drive it too soon the acceleration is very sluggish. Once it passes it runs just fine.

The dealer said the o2 sensors and the cats are just fine, and someone suggested it could be and EGR valve or something along those lines, and that whatever the "undefined" code is, is more than likely causing the P0430 code. I'm still learning about how a lot of this stuff works as this is my first non-junker car, so just assume I'm a total noob with this stuff. Any insight you could give me would be greatly appreciated. Thanks!

cruisin5268d

Welcome to the forum!

Just a thought - you could have Ford re-flash it to factory and go from there. Then buy a tuner (several vendors on this forum offer tuners and tunes, such as American Muscle.com and Bama tunes) and use that to address any issues.

Why can't the dealer tell you what the undefined code is?
Hindsight is 20/20, but you should have stuck to your guns when you got the vehicle and made them address the issues.

I wouldn't call you exhaust set up "extensive" if you still have the cats.

jz78817

that's horse****. P2195 is a generic (non-manufacturer specific) code which means "O2 A/F Sensor Signal Biased/Stuck Lean." something's ****ed up on your car. a catalyst efficiency code means one (or more) of the catalytic converters on your car just aren't working right. modern cars have multiple O2 sensors. the upstream ones are in the exhaust header, and the PCM uses those to monitor its engine management. the downstream ones are after the primary catalysts, and the PCM uses those to make sure the catalysts are there and working properly. If you're throwing catalyst efficiency codes, you have a non-functioning cat.

jpplaw

Yeah, you have a bad cat. Chances are you'll also get a P0420 soon for the other cat too. I'd change them before they melt, fall apart, or clog up. Believe me, you do NOT want that to happen.

The K&N might be causing your P2195 code, its really doing nothing for you so I'd get a good CAI like a JLT to replace it and a good tune from somewhere like Brenspeed or Bama, etc. (I know its expensive but its definitely worth it).

The minute or two after start-up thing means something is wrong during "open loop," meaning the existing tune is screwed up (more than likely its probably a combination of the K&N and the tune). Open loop only lasts 120 seconds after start-up and during that time, the O2's aren't working. The P2195 will only set after the cars goes into "closed loop" and the front O2's start working.

You also go into "open loop" at WOT, so I wouldn't go mashing the gas until the tune gets straightened out. You do not want it to be lean at WOT.

Also change the plugs, and clean the throttle body and MAF sensor.

PonyBoy06

Dammit. I was really hoping this wasn't the case. I've had a few people tell me that there are a number of things that can set off a cat code.

Is it at all possible that the messed up tune is what's causing the problem, and the cat is fine? Would there be any harm in addressing that issue first to see if the problem persists afterwards, or is this code absolutely 100% indicating a bad cat?

Forgive my ignorance, but what does WOT stand for?

Thank you both for your help. Very much appreciated.

PonyBoy06

Forgot to reply to this, but I wanted your input on what I asked the other two responders--should I assume it's a bad cat, or just start with having it reflashed/tuned, etc, and then go from there?

Honestly I'm tired of having the dealer give me the run-around. It's a decent drive and I know they're just going to keep telling me it's not a big issue so they won't have to do any serious work on it. I'd rather fix what I can myself and go to someone honest to do the rest.

It may not be extensive, I was just quoting the dealer on that. But removing the cats would have to be a temporary thing, until I have to go through inspection, correct?

jz78817

not really. The way this works:

the front (upstream) O2 sensor is what the engine uses to monitor its operation. The electrical signal is an oscillating signal which varies as the engine goes between slightly rich and slightly lean. The rear O2 sensor just monitors the catalyst; it should be a much more stable signal and not oscillate much if at all. If the signal coming from the rear O2 sensor is too similar to the signal coming from the front O2 sensor, the catalyst is no longer functioning correctly and the PCM will set catalyst efficiency codes. It's pretty much the only thing that can cause those codes.

you could have multiple issues here. Cats usually don't just up and die*, something kills them. Overheating, poisoning by contaminants such as lead, and so on. if the car has a dodgy tune and isn't managing the A/F ratio properly it could have caused the damage to the cat(s.)

Wide-Open Throttle (i.e. "flooring it.") When the PCM sees the TPS report the throttle is open past a certain point, it will switch to a pre-set fuel map which runs things slightly rich to prevent detonation. You do not want to risk detonation which can easily happen if the A/F ratio is too lean. Detonation will kill an engine quickly.

* the only really "random" failure I've seen on a catalytic converter is if the ceramic honeycomb substrate cracks.

PonyBoy06

Ok. Thanks for the explanation. Like I said, I'm a bit new to all of this, but forums like this one have definitely been a great education. I appreciate your help. Guess it's time to go cat shopping...any recommendations that won't destroy my wallet?

Simon1

If you want to stay street legal get a new midpipe with cats, if not, get something catless.

Then either take off the K&N or get something that works with a tune.

cruisin5268d

Assumption is "The Mother of all Screw Ups." Okay, maybe that doesn't apply here but I still like saying that. It does seem as if you have a cat issue and one/more needs to be replaced...but maybe not. If you like the tune and tuner idea as a performance mod, then might as well get that anyways and start from there. If you're not wanting that anyways, then replacing the cats might be the better route.

I am pro-cats. These cars are tough enough on the environment and I think it is irresponsible, even if legal, to remove the cats. I know many here feel otherwise but at the end of the day that affects air quality for all of us. I'm not sure about your state but cats are required in Texas and pretty much every populated / environmentally conscious / liberal / smog-filled state. There's probably an exception to the rule but I couldn't tell you off hand which states do NOT require cats to pass inspection.


Off topic, but I commend you for your approach here. You came to this forum seeking people's input - and you appear to actually be interested and appreciative of what's being said. Many people come to this forum, ask the same old questions, and then reject the input of forum members. Kudos to you.

Negative kudos to your dealer for being so lousy.