OBDII : LONGFT1 -15% at idle

[Biomecanoid]

Hello,

 

I just checked my car with the OBDII tool and found the Long term fuel trim to be -15% when parked idling.
I do remember both short and long term fuel trim being at 0% a few days ago.

I don't believe this is normal, Anything I can do ?

 

Thank you

Chris

[flash22]

Any work been done on the car ? What's the MAF flow/MAP reading? can you check it with another scan tool as it should throw a lean code and be running like 3 legged donkey

It could be a slow O2 sensor, again you need to look at the values

[Biomecanoid]

7 minutes ago, flash22 said:

Any work been done on the car ? What's the MAF flow/MAP reading? can you check it with another scan tool as it should throw a lean code and be running like 3 legged donkey

It could be a slow O2 sensor, again you need to look at the values

On 23/05/2021 both short and long fuel trim was at 0%.

Air filter is clean, ( also run the car without the filter no change ) and on 10/05/2021 I added to the fuel STP Fuel System Cleaner.

I thought since the car is 15 years old and still with the original fuel pump it must be dirty

I don't know if its relevant but I also have a CAT_RDY INC.

Car is running fine no errors codes or check engine light, nothing weird

I will upload photos of the readings from the scan tool.

[Biomecanoid]

Photos: 

[flash22]

iat is at 37 degrees what is the outside temperature ?

[Biomecanoid]

3 hours ago, flash22 said:

iat is at 37 degrees what is the outside temperature ?

Yes we have a hot summer here :P

[Biomecanoid]

Any ideas ?

[Biomecanoid]

Anyone cares to contribute ?