A few weeks back I stuck an AMS Intake on my X in advance of a couple more mods I had planned for the next few weeks (exhaust + tune). It's been driving fine, but yesterday I threw a pair of codes. I was on the highway under light acceleration in 5th gear. It did not go into limp mode. The codes were:

P0171 - System too lean: Bank 1

and

P1320 - Ignition timing retard insufficient

I have the first reflash, but was turned down for the second. Since I planned to get tuned come spring, I let it go. I read that there's a TSB for this, but now that tuning is a few weeks away, is it worth taking the intake back off to get it in to the dealer? It doesn't seem worth the effort. What do you guys think? With the car running so rich all the time, I'm surprised by the too lean code.

The internet says P0171 may also be caused by an oiled filter dirtying the MAF sensor. The AMS intake uses a K&N filter. Is there a way I can tell if the MAF is dirty by looking at it?

I also got this freeze frame data from the P0171 code, if anyone is interested. Some of the stuff is kind of interesting. I didn't know all this got logged when you threw a code:
Fuelsys1: CL
Fuelsys2: N/A
Load_Pct: 14.9 %
ECT: 180*F
LongFT1: 12.5%
ShrtFT1: 7%
MAP: 15.1Hg
RPM: 3313
VSS: 70MPH
SparkAdv: 40*
IAT: 95*F
MAF: 2.746 lb/min
TP: 20.4%
RunTm: 223 sec
Evap: 0%
FLI: 62.7%
Baro: 28.9Hg
Vpwr: 13.989 V
Load_ABS: 35.6%
EQ_RAT: 0.999
TP_R: 14.1%
AAT: 95*F
TP_B: 20.8 %
APP_D: 29.0%
APP_E: 14.1%
TAC_PCT: 14.1%

 

both those codes are from the intake with no tune... the building of boost at highway speeds is what caused the lean code... get tuned for the intake and you will be fine.

 

If you're getting tuned soon don't bother going back to the dealer, especially if they've already turned you down. The problems you're having are from adding the intake without tuning for it.

Anything else odd happening since you installed the intake? And does your car ever "stumble" when you go part-throttle while cruising?

 

I figured as much. I'm getting tuned in the next few weeks, so I'll just avoid highway acceleration as much as possible until then.

Of course, I can't say I've read any other posts where someone needed a tune for just an intake. Usually they do well because they lean out the too-rich condition that already exists with the stock tune.

The car's been behaving fine. If anything, it's been significantly better since the intake. I get idle-dance less often (where the idle bounces around when stopped), throttle response has been improved, and I haven't encountered any stumbles. All of which existed prior to the intake. I've been driving it like this for a few weeks now with a fair number of highway miles, and this is the first time it's thrown a code. The conditions must have been just right. I doubt I do 70mph in 5th @ a 20% throttle position very often.

 

My dealer stated that they would service anything for me as long as the cat is on the car.

 

I never heard anyone throwing a code either for just having an intake without a tune. I guess I'll have to swap the stock intake back on when I decide to go on a road trip just to be on the safe side. I would get a tune but I just can't make up my mind which vendor to go with.

 

Strangely, the Service Engine Soon light went off today. I made sure not to clear it in case I decided to take it in, but if the condition doesn't present itself again I guess it just clears it automatically. I was surprised.

 

With no Tune I also get the P0171 with the AMS intake every now and then. It also happens when I am driving it lightly on the highway. Easy way to fix it is to drive it like you stole it. The car still runs pig rich at WOT and will make the code disappear.

 

I get the P1320 code every so often (with stock intake), I just cleared it a week or so ago recently but seems to pop up once every couple of months or so. In the past I've been taking it to the dealership and all the tech does it basically clear it. He says if I bring it in again with this code he would have to log it in with Corp Mitsu to see if there is a permanent fix for it instead of basically clearing it.