89 S5 Vert cuts out on left turns!?

[RETed]

Do you have something that can show you fuel pressure?

If so, there is a "dead end" pressure spec for the fuel pump (at full voltage).
That's the easy one to check...

Next, you'd need to be able to watch fuel pressure at the fuel rail, which will usually call for a "T".
Run the gauge to the windshield and tape it there so that you can watch it while you're driving temporarily.

If it is fuel (pressure), it's either going to be a drop if fuel pressure due to a mechanical failure, or an electrical one...


-Ted