[Sniffer500]

My 2008 957 CTT has been stumbling (almost like a vague misfire) for a little while and I think its getting progressively worse

I changed the coils and plugs recently as a first step (all new parts, latest version of the coils) but it didn't help

I`d swear the issue is not so noticeable when the vehicle is cold and creeps in as it warms up.

I used to just notice the smallest stumble when accelerating from low RPM (classic coils I thought hence why I changed them) but lately I also notice it when accelerating hard even in the 3000 - 4000 RPM range, no real pattern except that it`ll lose power ever so slightly for just a split second and feels like a misfire

I`ve scanned it with Durametric and there are no relevant fault codes

Any ideas? I`ve read on your tech guides that dirty injectors can cause these type of symptoms (stumbling etc) - any way to verify (check values on Durametric or something)?

I know the fuel pumps and high pressure pumps on these cars can be problematic so would these symptoms be indicative of either of these failing?

Any help would be greatly appreciated