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P0171 Code but car runs just fine....How concerned should i be to drive it....

22K views 12 replies 5 participants last post by  SRivers33  
#1 ·
I should mention that the car was just repaired from a wreck where the FMIC, bumper, fender, etc removed and replaced. I have Read the guide to this particular code and am going down the list but need to drive a bunch tommorow...

My A/F gauge seems to read about the same (13-15 during normal driving) except when at idle when it goes to 17,18+

This to me means its likely a loose/cracked vaccum hose (Though my vaccum gauge reads the same as it always does), or a pipe somewhere not tightened down enough, though the car boosts just fine.....

I have tried new fuel and cleaning the MAF

Tommorow i'm going to do a smoke test.

How worried should i be to drive it? Like i said, it seems to run fine. Any help tonight is appreciated! Thanks!
 
#2 ·
Your AFR should be at stoich at idle (14.7:1), and normal driving shouldn't be any higher than that unless you're coasting. You have a leak somewhere in your intake tract post MAF or in the charge piping as you suspect.

I wouldn't be driving it around until you get it fixed.

Has this car been tuned? Also, is this a wideband sensor/gauge?
 
#3 ·
It's an AEM Wideband yes, it has been tuned, on E85 over a year ago, i am planning on getting it retuned once i chase down the p0171.(I really need to update my profile and sig).

So its for sure a leak? What tells you that may i ask?

So its going to be in a vaccum hose somewhere or one of the pipes is loose...

Yes?
 
#4 ·
To be fair, more things could cause the leaner AFR's than just a boost/intake leak, but in the OP you stated that the FMIC had been damaged and replaced. This makes it much more likely that it is something in your intake or FMIC piping than to be any other cause, so that's where I would start. Also, judging by the fact that there are no other codes where often times you'd see one (related to O2 sensor or MAF typically), it seems more likely to be a leak of some kind than anything esle.

Could also be a fuel pump on the way out, an exhaust leak near the O2 sensor, or bad O2 sensor (either the factory one the car uses for fueling, or your wideband O2). But like I said, given the conditions, I'm betting on a leak somewhere.
 
#5 ·
Thats what i thought (In regards to the multiple posibilities), but i agree, the intercooler itself wasn't damaged but the piping to it was so that was replaced and of course in the process of removing and reinstalling everything i'm thinking a hose either cracked or wasn't tightened down enough.
 
#6 ·
That's the lean bank 2 code, right?

I've been getting that intermittently myself. I always just turn it off with a battery reset. Annoying to say the least. Thought it was due to an exhaust leak I had, so I replaced the gasket to get rid of the leak, but it still came back after about 500 miles.
 
#7 ·
Bank 1 I believe, I'm sure something is up though because of my A/F reading. It's also idling about 250rpm higher than normal.
When I delete t, it comes back within 10 miles of city driving, usually the first time I let it sit at idle and the A/F climbs to 18+

It sat at the body shop for a month and was great before going in so I feel like it's got to be something they removed and reinstalled.
 
#9 ·
You want that fixed ASAP. Drive it to get it diagnosed and/or buy replacement parts, but seek alternate transportation otherwise.

Mikie13 said:
That's the lean bank 2 code, right?

I've been getting that intermittently myself. I always just turn it off with a battery reset. Annoying to say the least. Thought it was due to an exhaust leak I had, so I replaced the gasket to get rid of the leak, but it still came back after about 500 miles.
You're getting a lean code (not an evap code)? I thought you were getting the gas cap code like I was...
 
#10 ·
You want that fixed ASAP. Drive it to get it diagnosed and/or buy replacement parts, but seek alternate transportation otherwise.



You're getting a lean code (not an evap code)? I thought you were getting the gas cap code like I was...
No, lean bank 2 code, post cat or something like that...I forget the goddamn number.

It's currently off and has been for the last week...we'll see how long I go til it pops back up again.
 
#13 ·
Hilarity hath ensued here...today we couldn't get a smoke tester so we tried propane with a hose, moving the end of the hose around the bay waiting to hear the idle change.....
........
.........
Crickets
.........
.....Nothing happened, so we put the hose right up to the intake.....Nothing happened.....


we moved into the realm of dumb and used maf cleaner, sprayed it on the filter/ got an idle change so we sprayed that around the bay.... ..
....
..Nothing again....I cleared the code/ pulled off the filter and intake pipe and cleaned them a bit...and boom.No more code, A/F gauge reading about 15.2 and it's been fine all day.
.