Car runs as sweet as a nut (2003 3.2 Elite Auto) and shows no codes. 50,000 miles on clock.
A couple of days ago I replaced the cam cover seals/spark plugs/fuel filter/crank ventilator box and HBV (irrelevent really). All genuine parts.
Prior to this the car flew, I know the speeds below are normal but it got there pretty rapid.
50mph in first gear, 85mph in second, 128mph in third gear and in the right conditions it would see 150mph on the clock and did not need that much road to get there. (I have a very long driveway)

After changing the above parts (the spark plugs/fuel filter being the only things to affect anything) the car now seems so flat top end power wise. It seems to run out of puff around 125mph whereas before it would fly up to 130-135mph almost anywhere..
I have checked to see if I forgot to re-connect any vacuum pipes but can't see anything amiss. Idle is rock steady, power is smooth and driven normally you would not notice anything was wrong. the kickdown still pulls hard low down, it is just top end.

As said, there are no codes showing and it runs perfect apart from this but I want my missile back. I've been driving like Miss Daisy for months now but I like to know the power is there. :-/ :-/
All replaced parts were genuine parts.
Has anyone come across this before as I have obviously missed something.
TIA
Regards
Alan