Originally Posted by
Jon
The only way to be sure is to pressure test all the pipework between turbo and throttle butterfly. There are various different ways of doing this, but basically seal off each end, and introduce pressure somehow. A bicycle pump is too weak to help, and the airline at the garage is a bit OTT. If you can hear, see, or via washing up liquid see bubbles anywhere, there is a leak.
Fuel cut will have you headbutting the windscreen. It is violent, and no-one would describe it as a misfire.
The problem with original fuel pumps, is that they do wear out and fail (100,000miles is a random figure to quote) and can fail suddenly leaving you stranded.
Worse than that, is that before failure, they could be letting the engine run lean. That is why most SXOC people would recommend replacing the standard pump even if there are no bad symptoms today.
Weak coil packs will first show their weakness when under heavy load and high revs.