I have a terrible consumption accent Hyundai year 2000 and 1500 CC (14 liter at 100 KM)
I put octane 92 I was replaced my oxygen sensor and electronic sparkle NGK 1.1 and was clean TPS and MAF and i think not have any leakage in air system because i detected by water and soap and was clean my air filter my exhaust pipe is good and not have any bore
in the morning my exhaust pipe output white water
the injector i was clean and detected it's by machine named ultrasonic
my check lamp is (on) i was detect the fault at the computer.
the fault is
P1123 Long term fuel trim, at idle - mixture too rich
P1128 Long term fuel trim, at increased engine RPM - system too lean
Hyundai on the site saying detect the MAF and TPS sensor
(=95 Check that the Mass Air Flow (MAF) Sensor (P / N 28164-22610) operation meets the specifications listed below. If the MAF sensor output is significantly lower than the reference value (10% or more), then replace the MAF sensor.)
The TPS must to be 0 at IDLE this is ok and at RPM 2000 to be 3.5, but I have a 4 and then for 3000 to be 5.1, then I have for 5.5 and in some time at 3000 RPM is same signal
And MAF in the idle to be 2.8 this ok and at 2000 RPM to be 6 but in my car is 7
in the Hyundai site if the output lower the specs. must replace the MAF but in my case the output is higher.
i hope found the solution for this case.
the fault 1128 detect when i buted the octane 80 with 92