Quadrphnia

At operating temp (3 bars) when revving at or above 3000 RPM the revs will "pause" when letting off at exactly 1500 RPM for about a quarter of a second.

This does not happen anywhere below 3000 RPM, only at or above. It feels deliberate, particularly with the exacting nature of it, but it also feels unnerving. You can distinctly "feel" this pause and the car ever so slightly shimmies.

Any ideas? If not, would someone mind replicating my situation? This all happens in park. 2008 ISF, 44K miles and it's about 40 degrees outside today.

lobuxracer

iTrader: (2)

It is deliberate. There is a fuel cut off at 1800 rpm - the injectors stop working on deceleration until 1500 rpm. It helps dramatically with emissions control for the EPA test.

Quadrphnia

As always, thanks Lobux.