MK2 Golf with MK3 engine issues

Hi All,

got a 1990 MK2 GTI with MK3 AHU engine, PD130 turbo set up.

Been having a few issues, the turbo goes in limp mode quite often over 2k revs and then next time it wont. Few months ago I lost the accelerator pedal gradually eventually it died and it turns out where the sensor has been installed it had been placed in a bag to protect it but water had gathered inside and corroded it so it was cleaned up and has worked flawlessly since.

A few days ago, in first gear I pulled out quite quickly from a roundabout and used quite a lot of the rev range in 1st gear, when I went to change to 2nd the turbo "overspooled" and then engine cut out. it wouldn't restart instantly and when did restart ran very lumpy for about 2 minutes and then settled to normal. it boosted fine after (apart from the usual limp mode)

yesterday I started the car after not driving it for a few days, I noticed straight away it didn't seem to be accelerating like normal, I seemed to have to press the pedal further than usual. 20 mins into drive I lost the pedal, quick restart and it was fine.. then started doing it again.

I've had to dump the car in a safe place for now, basically if I start the car its fine, if I blip the throttle however once revs go over about 1600 the pedal dies and the car sits at about 1800.

Whats likely to be causing this? throttle position sensor? brake sensor?

Any ideas on the turbo overspooling/ cutting the engine?

I don't have VCDS (only Carista and Torque but neither scan this car) so will have to wait for Tuesday before can borrow a friends VCDS.

Anybody?

Got an error code 00519 intake manifold pressure sensor

i have vcds, for first thing, not using it right, and theres no real material or info that if in wrong usage, not being adept in that, and you now cannt get it back right, uuum that will add the shop hook-up base charge, to now diagnostic, and next step or two-fee, be quoted up front.
CEL?
so my 1st opinion here, for 1: all those nice and needed vac routings and,,.., so now the one in the ecm(im a mk3) is a real good1 right here to make sure you replace, and the whole lot, trace, correct, replace. that nice braided, 4-or-5mm hose. yup, check 1st.

Replaced the brake sensor, still got an error code for brake sensor even though I clear it, it comes straight back.