Posted 02 May 2012 - 03:36 PM
I don't know what is "acceptable" but IIRC, LTFT +/- 20% sets off CEL. LTFT is designed to fluctuate and it is impossible for it to lock in to a zero reading or even close to zero and stay there...that is why you have a range of 40% before it is a problem. If you watch it on a steady highway cruise it will be much more stable than when you are in stop and go traffic. It is a problem when the engine management system cannot influence the variable parameters enough to keep the trim in control.
To answer the OP question yes, that is normal
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