My 2003 V70 T5 is throwing no engine codes, and yet it's missing and reporting reduced engine performance, especially when throttling on. When you really floor it it cuts power completely for half a second or so. I don't think I've felt the turbo spin up a single time since this happened.

It came about after a split coolant hose was fixed, but the cooling system is working well, so I don't think it's necessarily related.

All the coils are fine. Tried swapping out each in turn with a spare to be sure if this. Spark plugs are fairly new, cooling system checked, and transmission flush done a year ago. The only thing I can think of is a fuel supply issue. I'm hoping someone here can make other suggestions.