[V8] V8 suddenly running like a coffee grinder above 1700 rpm

[Fedor Veenhuyzen]

First of all...Merry Christmas to you all!!!

Well, my Christmas started nicely this morning! After nearly a year of no serious problems, my loved V8 choose Christmas morning to give me grieve and mess up my holliday...hahaha..Anyway, it has a problem above 1700 rpm.

*cold or running temp...makes no difference
*it runs great up to 1700 rpm
*it starts very well
*looking at the sparkplugs it looks like it runs rich
*O2 sensor has been renewed about 15000 km ago + it doesn't look like a defected O2 sensor, as it doesn't want to stall when getting up to running temp.
*above 1700 rpm it starts to misfire and looses power
*to me it looks like a fuel related problem. But I don't really have a clue what it could be...maybe the presure regulator?
*as far as I could see today, none of the vacuum hoses are sprung.
*fuelpump seems to run well
*airfilter isn't the problem either....but amybe its a clogged fuelfilter, but it doesn't sound/look or feel like a lack of fuel, more like to much fuel.

Hopefully someone can give me a clue.
Thanks from a snowless The Netherlands

Fedor
89 V8