cold car

[chazza]

when my 7 year old nissan is cold in the mornings, it looses power everytime i hit the footbrake for the first few minutes of driving. it starts fine and is ok if i use the handbrake.

Any ideas why it might be doing this and what i should do to fix it?

[qapmoc]

Well, the servo assist for the braking uses vacuum taken from the inlet mainfold so obviously when you use the foot brake (but not the handbrake) the brakes affect the inlet air system. By using vaccum this really means that air is being sucked into the manifold and this will weaken the mixture if it has a carburetor, probably the autochoke is only marginally correct. If it is fuel injected then it should not make any difference.