Car is running a Bit rough.

I have a LTFT of 15.67 on Bank 1 and 14.78 on Bank 2

these drop to 11-12 under load


How should I proceed? Is this a Vacuum leak?

 

What scanner do you have to check the car?
Can you get it to anyone who knows how to operate the SDD system?
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Yes, appears to be a vacuum leak. Have a smoke test performed to determine source of the leak(s).

Would be helpful to know vehicle details such as MY and engine fitted.

 

NT909

2015 Jaguar FTYPE R

 

Are you sure you're reading fuel trims?
These numbers look strangely coincidental to fuel ratios (14.7 is ideal stoich), and in PE (power enrichment) you are showing 11/12 and 12.5 is the hypothetical perfect PE. Of course, when in PE closed loop opens so won't read STFTs. And, you cannot read fuel ratios w/o a wideband but some systems do a "calculated" fuel ratio (albeit poorly)

I say that BC FTs, especially LTFTs are ideally best at 0% - 10%. If your numbers of 15.67 and 14.78 were really %s which means a critically lean mix the ECU is trying to correct, it would be setting a CEL (P0171; P0174) on any car I've tuned. At least based on the years of tuning I've done. Lean is more dangerous to engine health than rich is.

So, certainly, I agree if your FTs are really in the 15% range check for places where air is being drawn in anywhere past the MAFS. The "tubing" and connects past the MAFs are likely, but anywhere even the sensor connects at the SC.