EGR?
You're in the wrong forum. You need to start a thread over in the Evo 1-9 sections.

 

Well I too have this problem now.

After reading up on it, I know what it is and what I need to do. However, I still have a question....

Is it recommended to continue driving the car with this issue (CEL P0171) or should I revert to stock form?

Any help is appreciated, thanks!

 

I am not going to tell you what to do or not to do, but I have a question for you.

Did you buy a 30k+ car to "risk" damage when the vehicle is throwing a CEL to warn that something isn't right? I am not trying to be a smartass at all....really I am not but that is what you should ask yourself.

It was risk and reward for me, and the risk wasn't worth it. Would I have been fine to continue running the intake? probably, but it simply wasn't worth it.

 

I recently started to get this code (P0171) too but the weird thing is I'm running stock intake. I had WORKS drop-in filter but reverted back to stock since COBB AP didnt, at the time, have a map for it.

 

TunerHead, were you running any tune at the moment of your CEL?

 

Thanks for the reply.

Yes I am currently running the COBB AP canned stg2 for 91oct (with parts installed required to run map) and this is when the CEL was thrown. Strangely, I've been running this same map for a couple months now same parts, no changes and this CEL just recently started to pop up.

 

Has there been any major recent changes in driving style, environment, or major maintenance?

 

Summer, temps ranging in the 85-100 range with low humidity. Other then that no other changes. I've actually thrown this code in the morning and at night.

 

Ok so a week after doing my FMIC, and intake swap out I got this code. I was cruising at about 70MPH when the light came on, but it seemed my car was compressor stalling some (too much air) on part throttling. Seems the Forge recirc BOV, wasnt able to move the air enough, as the car would stutter on part throttle like I said. if I use the accel thru cruise it was fine, and if I did moderate throttle it would not create the same surging issue.

I currently have the Perrin FMIC TTR U/LICP and air intake stuff plus shield. I reset the code and did a search to find all this is a common issue, but can we up grade the MAF at all? I seen people going to a AFM system, but is it worth it? Input please!

 

Same code and found that my vacuum line for the fuel pressure regulator popped off. Time to get a zip tie on that bad boy.

 

I exchanged emails with David Boshur a few times early into my consideration for tuning and he was kind enough to warn me that ANY aftermarket intake was likely to thrown engine codes, as you're describing. The second post, replying well, said it all and I can only add I can also get that from a dirty MAF sensor from an oiled drop-in filter replacement like the K&N's. You can buy a $4.99 can of MAF cleaner from the parts store for that. IMHO, it's safer to remove the MAF housing and clean the MAF with it in the plastic rather than unbolt the MAF from it's housing. Taking the air filter box off is easy, and the MAF housing is one large hose clamp and a few plastic clips holding the MAF wiring. That way the MAF won't be damaged if you accidentally bump it, or heaven-forbid, drop it, while cleaning.

 

How dangerous is it to run with a P0171 (lean) code for a with a cold air intake for any length of time? Honestly, I want to accumulate more mods before heading down for a tune.

My baseline afr's hovered around 10.25 and peaked at 10.4. Although I'm throwing this code, I have a hard time believing that I'm at a dangerously lean afr.

 

I just got the same code on my 03 WRX. I took it into the shop for oil. They asked if I wasnted to clean my K&N filter so I let them. As soon as i left the shop I got the PO171 code popping up. Could it be because the guy didnt let the filter dry enough?
HAve you tried cleaning your MAF?

 

I didnt get a chance to read all the responses because I'm at work but.

P0171 is when your fuel trim is adjusting to the max of 15% or more. I used to get this code non-stop on a previous car. It was from a leaking BOV.

So check your vac/press lines and accessories.

 

It's really too lean, it's likely caused by the MAF being dirty (same "dirty" cycle as the air filter, clean both together.

The MAF, if dirty, will not register the actual amount of air flowing, telling the system that more is needed. That MAF is the really important sensor that does heavy lifting in the real-time "tune" of AF mixture. So when dirty, it lets more air in, causing System Too Lean code. Easy fix, but be careful with the MAF. I leave mine in the intake housing assy after I get the airbox dis-assembled to give it extra protection from accidental droppage.