I have the engine management light on the fault code is
P0171-00 (AF) System too lean (bank 1)
When I drive the car it feels like no difference in power
Has anyone got info on the problem
Thanks
Cosmo

I’m still trying to find the problem

Could try swapping MAF sensors over bank 1 to bank 2 and visa-versa, if code changes to P0174-00 would indicate a faulty MAF sensor, as code refers to MAF and Cat sensors, also possible air leak on air intake system. The two sensors are identical and interchangeable just look different as they are mounted at different angles. Only a suggestion.

Cheers
Col

I’ve not been in a hurry to remedy this as not caused any problem with performance
Sometimes I reset the engine light and no problem for a couple of weeks but then I’ll reset and comes straight back on
I’ve done a live data on both mass air flow sensors and getting different readings as shown in photo
Is this normal



Thanks
Cosmo

well -30 seams a silly value.
But worth someone else with the same engine checking, incase its a GAP problem.

next time check the long term fuel trims for bank 1 and bank 2

should be about 0-4
When it gets near 20, the light comes on

As I look at the car from the front which side is bank 1

L/H side. R/H when sat in drivers seat.

Cheers
Col

Thanks for the info

I’ve cleaned the mass air flow sensors and still getting same reading so I swapped the sensors over and still the same reading as before
I checked the long term fuel and the readings are

Checking other different live values I’ve found this

After doing a lot of research on web some people saying pcv diaphragm can cause the same fault codes
I’m getting a noise I can only describe as when you blow through a fag paper getting a vibrating sound
I can also hear a hissing sound coming from around the area of the diaphragm’s
If this could be the cause has anyone changed them on the 5.0 supercharged engine

If you have a hisssing then fix it

Last edited by Andy K on Tue Aug 09 2022 3:37am. Edited 1 time in total