Outer Limits 4x4 Board

hi i have a 1990 1.6 carby vitara it drives like a charm but when i get up to around 1000m above sea level it seems as if it is suffering from not enough fuel geting in to the engine has anyone had this problem or heard of it any suggestions on what to have a look at would be appreciated.

what i have changed:

spark plugs
fuel filter
put in carby overhall cit
all new vacume hoses in engine bay
all new fuel hoses

if there would be any thing else i should change plz tell me while the car is pulled a part in the garage

its probably running rich as the air thins out.... although 1km isnt all that much really... are you sure its not just the amount of uphills you're doing compared to when youre at home on flat ground???

Carby is heated by coolant water, if same as Sierra carby.
Sometimes the hoses get blocked, and I have seen the spacers left out, that are part of carby heating.
If water is too low, carby heating can run dry and fail.
If air is too cold, tcarbies can freeze up, especially if running a snorkle or cold air ram.
If you stop and idle for a bit, that can unfreeze them.
I have to turn off my snorkle, and suck air from under bonnet, when driving in cold mountains.

EFI may be the real fix

is the fuel pump pumping properly?

would it be the same problem, that some vitaras have when doing hill climbs? where the fuel pump isnt strong enough on steep angles.