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High LTFT at idel and LTFT increase with higher RPM
I have a 2008 Toyota Corolla E150 (european model) with 1ZR-FE engine. At idle my LTFT is at 8-9. As I increase the RPM to 2500 the LTFT increases to 12 if I increase the RPM further to 3500 - 4000 the LTFT increases to 15-16.
In town there is n o issue but as I get on highway and increase the speed and RPM (100 mph around 5000 rpm) I get an check engine light with code P0171 (please see attachment with the actual DTC freeze frames). I reset the code and I am fine until I get on the highway and again I get a code. I have a scanner and I can read the codes and see the live data. The injectors are almost new on the car (25.000 miles and original Toyota).
Can anyone point me to where to look. I do not suspect a vacuum leak since the LTFT increases with the RPM.
Looks like something is going on with the O2 sensors. Upstream is lean but downstream is pegged rich?? One of them is probably lying. Not saying that is the problem but it sure looks like a problem.
Have you noticed any loss of power? Or increased fuel consumption? Checking oil level and smell might give some direction.
If you trims get worse on higher RPM, this might be O2 sensor, but can also be an underperforming Mass Air Flow sensor (if it has one), fuel pressure (filter, lines, pump) or injector(s) for example. It's getting too little fuel, more likely than too much air
Definitely look at fuel lines i had one a while back the supply, return line and vapor line were corroded through. Also a good time to look at brake lines as they run right next to fuel lines which also had the same problem which is what the car got towed in for to begin with.
With the freeze frame data i would have to say something's up with the maf sensor as
~40 g/sec at 3787 rpm is really low should be up around ~90-100 g/sec at that rpm.
Check airfilter if it has not been replaced good time to do it with a cabin air filter and clean maf sensor off and recheck readings for maf afterwards. If no change in maf may need to do some testing but we will see.
