850 Turbo, 95, stumbles during hard acceleration-turbo

[MrOwl81]

I'm having the same issue as well, however when check engine light came on 3 weeks ago the only codes were for bad front o2, and cat efficiency. changed the front o2 (bosch), and a couple of week later symptoms returned with 435 (02 slow response code), have yet to check vacuum lines, will do so in an hour. could not changing out rear 02 possibly be the cause for problems to continue?

[V850B5254T]

A significant number of 850 Turbo owners in Denmark have had similar problems when using Bosch and other non-Volvo spark plugs.
I do not know what makes the Volvo spark plugs special, but they appear to have a quality not offered by any other supplier.

regards
oakey