What "Fuel Trim: Bank 1 (Add): System too Lean" mean exactly?

This engine only has one bank. The description is generic.

The code is for a system that cannot add enough fuel to maintain balanced air/fuel control. This can be caused by

1) Vacuum leaks

2) POSSIBLE MAF failure

3) Restricted fuel filter

4) Failing Fuel pump

5) Thermostat or ECT sensor

6) Failing oxygen sensor.

7) Exhaust leak before the oxygen sensor

Fuel Trim Bank 1

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RE:

What "Fuel Trim: Bank 1 (Add): System too Lean" mean exactly?

I have a vaccum leak before. I found the leak and fix it. I reset the codes and now I only have that one :

Address 01: Engine

Controller: 8D0 907 558 M

Component: 1.8L R4/5VT MOTR AT D01

Coding: 06251

Shop #: WSC 06435

17544 - Fuel Trim: Bank 1 (Add): System too Lean

...

This is all very interesting and wonderfull, but it really does not change a thing. "What will be, will be" Man can only surmise and wonder. Spiritually! your guess is as good as mine. It makes good reading tho! I am not going to get excited about this as some kind of omen. "Limited in his understanding and experience by his five physical senses, man compared to God is little better than an insect. His world exists for only a small distance in any direction, and yet he considers his opinion enlightened in all directions." God has given us some clues as to what to expect in the latter days. Do what He advices us to do and don't worry. It is all in His hands anyway!

Sounds like a bad fuel injector. I don't know the firing order, but it's probably the first one at the front of the motor. It could also be your mass air flow sensor. Usually when a maf sensor goes bad it goes into 'limp mode' and you get a 'system too rich' reading. Try to unplug your maf sensor and rescan and see if you get and different readings, and if that same code is also still there.

Try cleaning the MAF since it's easy and may help:

http://www.crcindustries.com/auto/content/prod_det...