“Unstable Engine Performance and High LTFT1 Reading Issue”

Alza · Wednesday at 7:38 AM

As soon as I start the car, it begins to shake and alternates between stabilizing and shaking continuously. When I connected it to the OBD2 , I found that the Long Term Fuel Trim (LTFT1) percentage was higher than the others, as shown in the image. What’s the solution?

Hec In Omaha · Wednesday at 9:22 AM

Looks like the computer is leaning out the air/fuel mixture since there are negative values being displayed. Bank 1 "Drivers Side" is really being leaned out. I would check fuel injectors. I would try replacing each injector on the drivers side with one from the passenger side and check your OBD2 readout. If your readout switches to LTFT2 "Passenger Side" then you will know which injector(s) is the culprit.

Hec

ikuo78 · Wednesday at 7:37 PM

Fuel trim is calculated from the O2 sensor value.
It would be a good idea to replace the O2 sensor upstream of the bank that is over 30.

Hec In Omaha · Wednesday at 9:42 PM

ikuo78 said:
Fuel trim is calculated from the O2 sensor value.
It would be a good idea to replace the O2 sensor upstream of the bank that is over 30.

If the O2 sensor was faulty, wouldn’t he get a code for that too? Like O2 heater, O2 voltage etc.
Hec

ikuo78 · Wednesday at 11:24 PM

Hec In Omaha said:
If the O2 sensor was faulty, wouldn’t he get a code for that too? Like O2 heater, O2 voltage etc.
Hec

In most cases, a DTC will be issued and a check light will come on.
If the damage does not meet DTC standards, nothing will come out.

If I remember correctly,
Since the correction value is -, the PCM determines that the air-fuel ratio is rich and makes a correction to reduce the fuel injection time.
If the correction value is +, there is a possibility that the injector is broken.

Is there DTC?

“Unstable Engine Performance and High LTFT1 Reading Issue”

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