Thread: Long Term Fuel Trim

The so-called 'long term' is cumulative. It's updated and averaged continually like the average fuel consumption on a long trip...The numbers are pretty well close enough. The 16.4 and 14.8 indicate there's an air leak somewhere and the closed loop system is adding extra fuel to try and maintain the ideal air/fuel ratio. The max. value is 25 once the leak is large enough!

By air leak I mean that air is being drawn in post the MAF. I'd suggest checking the hoses from the valve /rocker covers, the integrity of the plastic hose tail which screws into the manifold (they can crack from the heat) as well as the large jubilee clips used on the air intake hoses. If that doesn't fix it, relieve the tension slightly on the bolts attaching the upper inlet manifold...beginning with the outside ones first then retighten beginning with the middle ones and work your way to the outside ones...

There are several posts in the P38 section with screen shots from the Torque
app. on this very issue which may assist.