Lack of power ??

[Blowhole]

Can any one help I have a 2.0 cu in my t25 ,I seems to have a mind of its own ?
It loses power when it wants to . I will be driving for hours sometimes and it's
Fine at 60 mph all day but now and again it drops down to 30 and has no power at all.
Once it parked up for a while its fine for days ?
New carbs . Full decoke and service done !
Cooling flap fully open and electric fuel pump fitted ?

[Blowhole]

Could this just be a simple matter off wrong engine oil???

[faggie]

fuel starvation due to rust change the tank if its the original one