I had all six glow plugs replaced thinking it had something to do with that but still no luck. The car is at an indy dealer and hasn't done it for them for the four days it's been in there, no error codes either. I guess I'll have to take it to the dealer to get it diagnosed... was trying to avoid since the second hand warrantee only covers certain indys.

I've also been thinking might be a faulty/clogged injector, but I would imagine that I would notice a loss of power when driving. I've been thinking of adding an injector cleaner to see if it helps, anyone has had any luck with those?

Dont want to go crazy changing things either, already paid 400€ for the glow plugs...