intermitent lean (p0171/p0174) codes..
Thread Starter
TECH Junkie
iTrader: (5)
Joined: Feb 2007
Posts: 3,183
Likes: 3
From: Key West, Florida
intermitent lean (p0171/p0174) codes.. for the past 6 months or so i've been setting off what appears to be an intermitent lean condition.
the SES will turn on, sometimes even flash for several seconds. then generally after 3 starts it turns off (which means the condition is gone).
the car never stumbles or stalls and has always gotten reasonable gas mileage around town.
up untill recently i've been unable to scan it.
the last time the SES was on it was P0171 which is bank one. i figured the 02 sensor was going bad, but figured i'd see what happened after it turned off and then came back...seeing if it reappeared on Bank 1.
well this time when i scanned it it showed p0171 as expected, and p0174 which is the same code for bank 2.
looking at the LT fuel trims they appear to be right around 25%, which if i'm not mistaken is pretty freakin high.
note:
o2 sensors were replaced after flooding in wilma...in oct of 05. and have maybe 5K miles on them.
NOW....
could ethanol be doing this to the car?
could a dirty MAF be causing it? i have a k&n and havn't cleaned the maf in 5yrs.
i plan to look over the vacumn lines to see if that's the problem.
any other suggestions??
the intermitent part of it is what has me baffled.
by the way i drive 7 miles each way to work...generally 2-3 times a week...that's about it.
taken it on several 50...100...150 mile trips in the past months with no SES issues on some, but it shows on others.
grrrr.....
the SES will turn on, sometimes even flash for several seconds. then generally after 3 starts it turns off (which means the condition is gone).
the car never stumbles or stalls and has always gotten reasonable gas mileage around town.
up untill recently i've been unable to scan it.
the last time the SES was on it was P0171 which is bank one. i figured the 02 sensor was going bad, but figured i'd see what happened after it turned off and then came back...seeing if it reappeared on Bank 1.
well this time when i scanned it it showed p0171 as expected, and p0174 which is the same code for bank 2.
looking at the LT fuel trims they appear to be right around 25%, which if i'm not mistaken is pretty freakin high.
note:
o2 sensors were replaced after flooding in wilma...in oct of 05. and have maybe 5K miles on them.
NOW....
could ethanol be doing this to the car?
could a dirty MAF be causing it? i have a k&n and havn't cleaned the maf in 5yrs.
i plan to look over the vacumn lines to see if that's the problem.
any other suggestions??
the intermitent part of it is what has me baffled.
by the way i drive 7 miles each way to work...generally 2-3 times a week...that's about it.
taken it on several 50...100...150 mile trips in the past months with no SES issues on some, but it shows on others.
grrrr.....
Thread Starter
TECH Junkie
iTrader: (5)
Joined: Feb 2007
Posts: 3,183
Likes: 3
From: Key West, Florida
how would an intake gasket work fine for weeks, then throw codes a week later.
i cleaned the maf sensor monday nite, drove it to work and home tues, then to work this AM...
no codes.
plan to thow the scanner on it this weekend to see what the LTFT are doing.
i cleaned the maf sensor monday nite, drove it to work and home tues, then to work this AM...
no codes.
plan to thow the scanner on it this weekend to see what the LTFT are doing.
I agree with the vaccum leak possibility, my car did this just a few months ago and I had a small vaccum leak on the underside of the PCV tube where it connects to the intake. That little angled rubber piece had a small leak in it causing the lean condition.
Its a gasket is it not? Gaskets go bad. I do this stuff for a living everyday. If you are throwing lean codes on both banks you are getting air in AFTER the MAF. You could have lazy 02 sensors, but its not too common for them to go out in pairs.
Thread Starter
TECH Junkie
iTrader: (5)
Joined: Feb 2007
Posts: 3,183
Likes: 3
From: Key West, Florida
just drove 260+ miles with no code...starting the car multiple times a day.
tripped a code on the way home today.
code was p0171
starting the car several times...gas station, parking lot, then once to try to download the code (failed...laptop issue).
on the last start....the SES turned off on its own.
looking at the data...one screen says my LTFT are both 25...i assume percent.
and in another screen it says "average LTFT" which is something like 17.xx bank one, and 19.xx bank 2.
tripped a code on the way home today.
code was p0171
starting the car several times...gas station, parking lot, then once to try to download the code (failed...laptop issue).
on the last start....the SES turned off on its own.
looking at the data...one screen says my LTFT are both 25...i assume percent.
and in another screen it says "average LTFT" which is something like 17.xx bank one, and 19.xx bank 2.
