AHU mTDI surging, bucking [SOLVED]

[Sohio]

installed a 300tdi rover pump on my 98 jetta and its bucking like crazy.
ONLY happens under load . can rev at idle and make boost no problem.

heres a video
http://youtu.be/osrxlvUlMlg

heres where im at:
 
prior to installing the pump the car ran fine , boosted as desired, all systems go.

the pump is a rebuilt from the UK so should be like new.
there is an external lift pump that functions correctly   
ive tried bypassing the lift pump. - no changes
replaced the large line going to the pump with a clear one and completely bleed out the system of air. - no change
checked for leaks in boost pipes and vacuums using break cleaner and there appears to be none.
looks to have plenty of fuel getting to the pump.
checked and double checked vacuum lines.

dont know what it could be. has anyone experienced this as seen in the video? 
is it possible that my pump is bad.
the rpms dont appear to be moving much
 just like the fuel is strobing or something.

[vanbcguy]

Man that's weird. It sounds great when it's not doing that.

So it'll cruise at a constant speed just fine?

Is your boost gauge steady?

[Sohio]

Man that's weird. It sounds great when it's not doing that.

So it'll cruise at a constant speed just fine?

Is your boost gauge steady?

the boost is not following the sound/feeling.
its steady and ive adjusting down and up using a turboxs manual controller.
really puzzling. i can start slow and bring it up very slow without it happening but as soon as i ask for power its a rodeo.

if the pumps bad i need to return it promptly.
just so strange that its happening now after a new pump with no other changes.

 the only other thing i did was block off the lower ccv. the elephant looking pipe was just left hanging open from a sketchy egr delete by the PO.

it ran fine with a beat up stock pump that had over 300k on it and was leaking from every seal.
 its almost like the car is bouncing with a steady pulse. not erratic. like a hit miss hit miss hit miss

[Sohio]

dont know if this makes sense. but it seems like there is only one problem. just dont know what or where. but when its on its good and when its bucking its on off on off. pulsing. it will start and rev in neutral all the way up, make boost, and you wouldnt know theres any problems.
also when it starts bucking it does not increase speed like it hits a wall and backs down then up down up down.

[Sohio]

Here's the full video
http://youtu.be/hCk-8vIuqDo
Little more context...

[Sohio]

I tried tightening the throttle cable and re wiring the shut off.
 Strange thing- I tried reverse in full throttle and it hauls ass no hesitation nothing .
Appears the car if not fueling while moving forward anybody have an idea on this??

[Sohio]

Well appearantly the sheeth on the throttle cable was loose along with the front engine mount not by a lot but enough that when the engine reared back under load the cable slacked and caused the bouncing/bucking. Tightening both the front mount and the cable sheeth solved it.

[vanbcguy]

Ha. Crazy. How is your accelerator cable rigged up?