96 850 turbo 257k misfires under boost

[hankbates]

Driving at 65 mph on interstate suddenly severe stuttering with check engine light on.
Slowed down without stopping, drove home with no issues keeping speed and throttle pressure down, about 50 miles.
Only codes I found were p0301 and p0306, cylinder misfire.
Checked fuel pressure on rail next morning and got 20-25 psi engine not running and also running.
Punp sounds normal
Drove car around block with no issues.
Fuel pressure regulator?

[hausmeister]

I experienced misfires once, and that was because I forgot to replace the sparkplugs - they were simply worn and would blow out under boost. Replaced them and fine again. But your issue might be different. A spark miss feels like a really sharp loss of power/shaking/stuttering I would say.

[volvolugnut]

Considering the much smaller gap (0.7mm compared to 1.20mm) for turbo charged engines, it may be wise to check your sparkplugs. If they are old it is likely the gap has grown wide.
volvolugnut

[scot850]

On the 850's we used to change the plugs every 30k miles and check the new plug gaps.

Neil.