I have been having issues with my SE stalling at times the last two years, the problem has been worse and more frequent the last few months. I have been cleaning the MAF sensor and throttle body where the car seems to run better for a while, however not with much consistency. If the car is warmed up or cold also regardless of temperature, the problem persists. At low idle, the car can stall. I replaced the throttle body and cleaned the MAF sensor yesterday, the car ran great for half an hour with a robust idle and the issue seemed fixed! However, later that night, the car idle would slow at a stop sign and the car would stall again. I have the code P0171 (system too lean) and the CEL light on. When the car ran great after the new throttle body, the CEL light was off.

Should I next replace the MAF sensor? There are MAF parts for $40 and also ones for $129, any MAF brand that is prefered?

There is one peculiar fitting in the PCV system which has been on the car since I bought her three years ago. There is a garden hose with a bolt in it serving as a plug to what seems to be part of the PCV system. I have included a picture of this. The garden hose has been there all along, however the stalling issue has gotten worse over the last three years.

Thanks
Christian

 

First thing I would do, is rip out that garden hose "repair" and put it back to how it SHOULD be.
Only after that would I try to sort out the P0171.

Putting the right parts back in might even fix your issue.

 

How do I determine the route and part that I need in th eplace of the garden hose?
Thanks

 

Can you follow the hose down to where it attaches to the vehicle? If so, snap a pic for us?

And/or look up some engine diagrams/images and see what they have - that your's doesn't?

 

I removed the garden hose and attached the line from the UFO looking 3” disc on passengers side of motor (PCV valve) to the garden hose hole that is on the cast top of the motor.

The car is running a bit better. Once it is moving, the car is fine. If I am slowing down at a stop sign, it might stall still.

I cleared the codes and got the same p0170 after half an hour of use. The car still stalled a few times.

get a new MAF next?

 

There is a sensor on the throttle pedal that operates the throttle body (similar to the brake switch) this can give problems with the throttle closing more than it should. This can be checked with some OBD2 tools.

 

I have a scanner, how might I proceed? Thanks

 

So you get both p0170 and p0171?

Have you reset the Throttle Body Adaptations? (need more powerful diagnostic tool, like GAP or similar)
Has the PCV valve (your UFO thing) ever been replaced?
Checked for vacuum leaks?
O2 sensors?

Could just need a new MAF too. OEM is PHF000140, I think Denso 197-6020

 

Actually just code P0171; I have not reset the TB. The PCV valve has not ever been replaced, that is the line I just reconnected from the PCV to the motor. I have checked for vacuum leaks just by listening, I do hear a bit of a hissing near the PCV hose I just reconnected at the motor end of the hose. I wiggle the hose and the hissing does not increase or decrease, I have also tried holding smoke near the fitting however I cannot discern any smoke disturbance. I read in another post that a rubber seal between the throttle body and the motor can dry and crack? The MAF was replaced in 2016. No idea on the O2 sensors, would they throw a different code?

I have also read about induction cleaning with seafoam, might that help?

is there a way to test MAF or PCV valve?

Not sure what to buy or test next?

Christian

 

Yes, TB seal can leak - some add a little sealant, or just replace if possible.
Sometimes the dipstick o-ring or oil filler cap can leak.
Doesn't take much.

New MAF in 2016? prob not the problem then, unless it was a cheap aftermarket.
Can you tell us what. brand/model # MAF you have?

O2 sensors are not likely, but possible cause.
Induction cleaning is usually fine, as is injector cleaner (in gas tank)

I tried testing my PCV by removing and creating vacuum - but couldn't confirm working/non-working
so I just replaced - it was cheap enough by LR standards.

I feel like with LR that the fix is usually simple and sometimes cheap, but the process of finding it can be very difficult and time consuming.