P0171
 

Ok guys so here we go. I bought my car about 4 months ago, as soon as I got it, it started to throw a P0171. Car runs great and I haven't had any serious problems with it. Bought it from a guy, car ran good and there was no CEL. I'm guessing he cleared it before he sold it too me. All it has done to it is a Injen CAI. Iv'e been reading a few things about why I would be getting the lean in bank 1 code but can't come to a full understanding. A few people say it could be because of the CAI but then others say that has nothing to so with it. Should I try my O2 sensors? I was also reading about Changing out vacuum lines. If doing so where would I go to get vacuum lines for my car? Thanks for all the help!

autozone

Most likely its the CAI... Idk bout the vacuum lines

most likely cause is the CAI. least likely is your O2 sensors. see if you can find a stock air box and put that back in and i bet you the CEL doesn't come back.

Damn I was hoping it wasn't the CAI! lol I'm thinking about getting the OTTP 3in, but I will try the stock air box. Thanks guys!

Bump! Can use all the advice possible!

start with putting the intake back to stock. CAI's are notorious for throwing a run lean code on our cars without either modifying the spark plug gap or tuning for it.

when you change the location of the maf it scews how the maf reads i wouldent worry to much about it it is and has been a common problem on these cars since they were new yhr only way to fix it is to tune it

not true, adjusting the spark plug gap is a valid option as well. i did it on mine when i had just an intake and without a tune it put my trims back to being dead on

yea i doubt that had anythig to do with it the trims and a lean code gm recognized the problem and put a fix for it their staged tunes

I just bought new plugs that I'm going to put in. What do you suggest the plugs to be gapped at?

start with stock gap. and see if things change.

and a staged tune is differen't i'm talking about stock tunes. you can adjust the gap to modify how strong or weak a spark is as well as it determines how long the spark fires thus changing how much air is needed before everything ignites. the maf is only half of what your fuel trims needs to calculate in. it also takes into account your o2 sensor reading. so if you fix the air issue in the combustion chamber and its reading correctly on the exhaust side your fuel trims will even out regardless of what your maf is reading.

ok thanks alot man

i would recommend stock gap and if you can get it tuned over playing with the gap but if you can't get tuned then play with the gap a little bit.

should you go with a bigger or smaller gap if it is lean?

if its lean you should tighten it up a little bit, you don't want to do too much maybe 2 or 3 thousandth of an inch should clear it up. it does take some trial and error. took me about a month to get mine to a point that my car liked.

Thanks for asking this! lol I went out and got some Denso's that were pre gapped at .34. Hopefully that will work. I had autolites in it before took them out and they were at .41!

UPDATE??? having the same problem here:cssNET:

Well I changed my plugs and I went to a stock intake and I'm still having the CEL so idk! lol Time to just zzp stage 2 and get a tune I suppose