D5 2009 Rev hanging between gear changes

[owen5861]

Good evening all,
So I fix cars all day but have been defeated by my own car,
Volvo V50 D5, 2009
that rev hangs between gear changes,
Accelerate up to 2500-3000rpm, dip the clutch to change gear and the revs will raise up to 3500rpm, hold there for 2sec then drop down, sometimes surge around 1500-2000rpm, then drop to idle,
here is the fun bit. No fault code, no air leaks, does the same with the EGR blanked, air flow disconnect, oil level is spot on, no smoke when revving up,
Got it remapped in case it was a software fault,
Fitted another throttle body, adaptations done, still the same,
Intermittent swirl flap stuck fault, but shouldn't cause the revving.
Clutch is slipping slightly after the remapping but it has 130000miles on it
Clutch switch is giving reading in live data
Open to suggestions before I drive it of a cliff.

[seanc]

These V50 and S40 had issues with ECU cables having connection issues causing strange problems... do you know if that's been done?

Long shot - if it's fly by wire accelerator, perhaps a pedal issue?

[5cilinder]

Originally Posted by seanc

Long shot - if it's fly by wire accelerator, perhaps a pedal issue?

Try one at the breakers.... or take a readout of the pedal with torque or vida