AAN takes ages to start and bogs down

[Jolfa]

Car is a '96 S6, just upgraded to K26 turbo, Walbro copy, 440 injectors, S2Central map, log manifold, usual RS2-ish stuff.

Since fitting the above, the car takes quite a bit of cranking to fire, and from idle if you touch the throttle lightly it will often bog or stall entirely.

Otherwise it goes, drive and pulls great and will settle back to idle pretty nicely (ocasionally drops to 800rpm before picking back up to a steady 1000).

I'm thinking MAF, boost leak or ****** plugs but thought I'd get a general consensus before I start pulling bits apart to find the culprit.

TIA

[LHD_Kid]

Didn't know Paul was doing chips for a K26?

Sounds like fuelling to me, but worth giving the MAF plug and pins a good clean.
Any codes stored?

[Jolfa]

It is in essence an RS2 unit

[rynaqui]

Likely symptoms of a dirty MAF (oil contamination)