Check Engine light+rough idle when cold

[Habs_Fan]

My check engine light came on just over a week ago, had the diagnostic code checked out, came back P0171: "System to lean (Bank 1)". At the time, the car was running fine so we just reset it and I was on my way.

2 or 3 days later the check engine line came back on (about 85km after turning it off the 1st time) in the middle of a cold spell, and i mean COLD AS F**K!! Day time highs have been overing in the -20's for the last few days and dipping to -30 overnight. So yesterday my check engine came back on. I'm assuming its probably the same code as before (P0171), but now my 2006 corolla idles extremely roughly when I first start it, even once I get moving, if I get to a red light and I'm idling, the engine struggles to stay alive at 600rpm occasionaly (usually idles closer to 1000rpm), it also stalled on me 3 times yesterday, all at red lights, had to give it a bit of gas to prevent the engine from chocking a few times. Once the car had properly and fully warmed up (after about 15 or 20 minutes), it wouldn't do this anymore (maybe a bit but not much), it only seems to do it when its extremely cold and the car is not warmed enough. I can't let my car warm up for 20 minutes in the morning, don't have the time or patience to do this.

So i'm wondering if the Idle control valve might need some attention or if its something else all together.

Remember its a P0171 code, which seems to be very common w/ corollas.

Any insight would be much appreciated, I don't want my car dying on me when its -30 degrees out.

Thank you

[Habs_Fan]

Update: I did read this thread after posting mine: p0171 leads to p0420??

So its sounds like it could be the intake manifold gasket that needs to be replaced... is this the likely culprit since I'm having issues mainly w/ super cold starts?? I would just like to have a list of possible culprits.

Is this an easy DIY job, and if I need to see a mechanic, what kind of expenses am I looking at to chg a manifold gasket?

thanks again.

[extreme one]

Originally Posted by Habs_Fan

Update: I did read this thread after posting mine: p0171 leads to p0420??

So its sounds like it could be the intake manifold gasket that needs to be replaced... is this the likely culprit since I'm having issues mainly w/ super cold starts?? I would just like to have a list of possible culprits.

Is this an easy DIY job, and if I need to see a mechanic, what kind of expenses am I looking at to chg a manifold gasket?

thanks again.

Many have done this including myself. Took me 1.5 hours and wasn't hard to do at all. There is excellent advice how to do this. Just search the first 3 or 4 pages on the 9th gen forum. At least its good to know brother you are not alone.

[juicedz]

Search through my thread on a low idle as well. I've been through the ringer on this one and still haven't tracked it down because it's not throwing a code. It's opposite of yours though. Mine idles fine when I initially start it up but once warm it idles rough everytime I come to a stop.

[extreme one]

Originally Posted by juicedz

Search through my thread on a low idle as well. I've been through the ringer on this one and still haven't tracked it down because it's not throwing a code. It's opposite of yours though. Mine idles fine when I initially start it up but once warm it idles rough everytime I come to a stop.

Have you changed the intake gasket? Did you disconnect battery? remember it will idle low until the computer learns its fuel trim values. This may take several days.

[Habs_Fan]

Update: So I thought the really low idling was because of the extreme cold but the last few days have been milder (still below freezing). My corolla still runs fine and all, except for the idling problem. Its still idling really low even as the outdoor temperature warms up. Worse part is that this problem isn't consistent, the really low idling issue is somewhat random, I haven't noticed a consistent pattern. Once I put the foot on the clutch, or if i'm idling at a light, the engine idles between 400 and 600rpm (averaging around 500rpm), no unusual noises, car seems to perform normally although it does vibrate slightly when it starts idling below 600rpm. Normally in the winter it idles closer to 1000rpm (or higher) and in the summer it will idle between 700-800 rpm, I've never seen it idle below 600rpm until the past 2 weeks or so.

The past few months I've also noticed that most of the time, on fairly short/moderate trips (2-20km), once i've stopped the engine and gotten out of the car, I'll hear a faint hissing sound (sounds like an air leak) coming from under the car, seems to be coming from the regions of the exhaust manifold/tranny/cat converter. The hissing only last a few minutes and eventually goes away. It doesn't seem to do this on longer trips or if the engine has been pushed or driven really hard. This leads me to believe that it could indeed be a gasket problem, but I would like some feedback about this.

So based on my research I think I've narrowed it down to 2 possible things.
-Gaskets (not sure which ones) need to be replaced
-Idling control valve needs to be repaired/replaced.

Any other possible issues? Maybe one of the MAF (or other) sensors? OR maybe the catalytic converter? (read something about the P0171 code and possible issues with the cat...)

I just don't want to waste my time and money on a diagnosis for this problem. I would also like to do the repairs myself if possible.

Thanks again

[extreme one]

Originally Posted by Habs_Fan

Update: So I thought the really low idling was because of the extreme cold but the last few days have been milder (still below freezing). My corolla still runs fine and all, except for the idling problem. Its still idling really low even as the outdoor temperature warms up. Worse part is that this problem isn't consistent, the really low idling issue is somewhat random, I haven't noticed a consistent pattern. Once I put the foot on the clutch, or if i'm idling at a light, the engine idles between 400 and 600rpm (averaging around 500rpm), no unusual noises, car seems to perform normally although it does vibrate slightly when it starts idling below 600rpm. Normally in the winter it idles closer to 1000rpm (or higher) and in the summer it will idle between 700-800 rpm, I've never seen it idle below 600rpm until the past 2 weeks or so.

The past few months I've also noticed that most of the time, on fairly short/moderate trips (2-20km), once i've stopped the engine and gotten out of the car, I'll hear a faint hissing sound (sounds like an air leak) coming from under the car, seems to be coming from the regions of the exhaust manifold/tranny/cat converter. The hissing only last a few minutes and eventually goes away. It doesn't seem to do this on longer trips or if the engine has been pushed or driven really hard. This leads me to believe that it could indeed be a gasket problem, but I would like some feedback about this.

So based on my research I think I've narrowed it down to 2 possible things.
-Gaskets (not sure which ones) need to be replaced
-Idling control valve needs to be repaired/replaced.

Any other possible issues? Maybe one of the MAF (or other) sensors? OR maybe the catalytic converter? (read something about the P0171 code and possible issues with the cat...)

I just don't want to waste my time and money on a diagnosis for this problem. I would also like to do the repairs myself if possible.

Thanks again

Again if it was my car the first thing I would do is change the intake manifold gasket. Search the forums on how to do it. My dealer says they do about 30 intake gasket changes at week on the corollas.

[juicedz]

Yea, initially I was planning on doing the idle air control valve but that's a $300 part and the intake gasket problem is more common. So I'm going with the intake route first since. Good luck with the struggle. Other than the vibrations @ idle I really enjoy the car. I'd like to be modifying it rather than fixing it though

[ryfly]

3rd vote on the intake gasket.